Modern interior design is a marginal subject involving engineering, art, ecology, environmental psychology and other disciplines. Its essence is to create a safe, comfortable, pleasant and beautiful indoor environment for human beings. Environmental psychology is an essential theoretical basis to support this major. Environmental psychology is a subject that discusses what kind of environment is in line with people's wishes from the perspective of psychology. Its application in interior design is mainly reflected in two aspects: 1) to study the psychological influence of living environment (all indoor environments for people's production and life) on people; 2) Study the requirements of people's psychological needs for living environment, and then adjust, improve and improve the quality of living environment according to people's psychological needs. 1 the present situation of environmental psychology in indoor environmental design Although the application of environmental psychology in indoor design has only developed in recent years in China, under the premise of "harmonious society", people have generally realized the importance of environmental psychology to the overall indoor environmental design, and some people are sparing no effort to copy plants, water bodies and rocks in nature into real life to satisfy their desire for nature. Especially with the rapid development of modern science and technology and the continuous improvement of people's material and cultural level, the trend of applying environmental psychology to interior design is becoming more and more obvious. In fact, many times, our production and life are constantly creating buildings and indoor environments that are incompatible with our favorite life. It completely violates our expectations of the real environment and even runs counter to the spiritual concept of environmental psychology. 2 people's cognition and feeling of indoor environment elements 1) visual satisfaction. The satisfaction of vision is mainly achieved through the treatment of indoor light (artificial light and natural light), color and modeling (modeling). First of all, let's take a look at the treatment of room artificial lighting in Mandarin Oriental Hotel (Bangkok), which has the greatest influence on interior design. The main lighting of the room uses table lamps as side lighting instead of unconventional ceiling lighting. Designers use materials that can produce diffuse reflection on facades, ceilings and floors to avoid specular reflection that is harmful to human eyes. In the treatment of natural light, double curtains are used to adjust the influence of natural light on human vision: the outer layer is made of translucent fabric, which is suitable for use when direct illumination of natural light is not needed; The inner layer is made of thick cotton linen with good shading, which is suitable for completely isolating natural light. In terms of color treatment, the designer used light yellow cotton-like wallpaper on the four facades of the guest room, ivory multi-space paint on the ceiling, relatively deep yellow cotton carpet on the ground, and a small area of contrasting color (ochre) on furniture such as tables and chairs. This collocation changes the tone of the whole space and unifies it in a light yellow color system that can express the feeling of "warmth" incisively and vividly. The whole space and furniture are basically rectangular shapes, because rectangles are the most balanced and comfortable shapes visually. 2) Good hearing environment. Good hearing environment is achieved by controlling sound source, sound transmission process and sound insulation. For interior design, meeting the requirements of hearing is mainly achieved by choosing decorative materials with different sound insulation coefficients in different spaces. Due to the strong activity privacy and high sound insulation coefficient, high sound absorption wallpaper and cotton and linen carpet are used on the facade and floor of the guest room, which enhances the sound absorption function and meets the quiet needs of the guest room passengers during sleep and rest. 3) Skin (touch) satisfaction. The satisfaction of skin sensation is mainly achieved through well-organized natural ventilation in interior design and selection of suitable surface materials with different tactile sensations. Therefore, when designers design the SPA lounge, they ensure the north-south permeability to the maximum extent, make it form a through airflow and improve the freshness of indoor air. In addition, when choosing materials that are in direct contact with our skin, we should also consider the needs of users. 4) Satisfaction with the sense of smell. Satisfying the sense of smell is mainly achieved through well-organized ventilation, indoor greening and reducing indoor smoke generation. Therefore, in order to improve the indoor olfactory quality, designers should first set up natural ventilation as much as possible when designing. In the case that natural ventilation cannot be completely realized, they should try their best to cooperate with the equipment department to set up artificial ventilation, and they can also choose the number and variety of indoor greening plants according to the space requirements.