"Science and engineering practice" is one of the three dimensions in the new generation of science education standards in the United States, and it is also a part of NGSS's transformation from formulation to concept. Science and engineering practice is an indispensable dimension and link in the process of students' scientific learning, and it is also the way and method for students to construct core concepts and cross concepts of disciplines.

Standards and performance expectations consistent with the framework must take into account that in order for students to fully understand the concepts of science and engineering, they must participate in exploration and practice, and make these concepts form and perfect discussions. At the same time, if students can't be provided with specific situations, students can't learn or show their abilities in practice.

Both the framework and NGSS show that every expected performance must be combined with relevant practice, which means that the learning of core concepts and interdisciplinary concepts is realized through practical activities, and the evaluation will not separate students' understanding of core concepts from their practical ability to apply science and engineering.

Teaching and learning science through scientific practice conforms to the essence of science, and it is also a teaching method with great changes and consensus in modern science education. However, it is obvious that the practice of science and engineering mentioned by NGSS is different from the past and has brand-new connotation, characteristics and system. This paper focuses on this to understand how to use NGSS practice development system to guide teaching.

The main features of the American education system are as follows:

1. Federal Government: The National Science Foundation (NSF) is one of the main institutions responsible for federally funded research and science education projects. In addition, other federal departments, such as the US Department of Energy, the US National Aeronautics and Space Administration and the US National Institutes of Health, also support science education to varying degrees.

2. State government: The state government is one of the main bodies to customize the curriculum standards of science education and formulate education policies. Each state has its own standards and tests, including the National Assessment of Educational Progress (NAEP).

3. Local government: In the United States, education is one of the jurisdictions of local governments. Therefore, every city and county has its own public school system, and private schools are also an important educational choice.

4. Private institutions and non-profit organizations: There are also some private institutions and non-profit organizations in the United States that are committed to promoting science education. For example, the American Chemical Association and american physical society provide training and support services for teachers, and also encourage students to participate in activities such as science competitions and summer camps.

Generally speaking, the science education system in the United States emphasizes cultivating students' practical ability and inquiry spirit, emphasizing students' understanding and application of scientific concepts, and emphasizing students' initiative and independent learning ability. At the same time, the system relies on the federal government, state governments, local governments, private institutions and non-profit organizations to form a complete educational ecosystem, which provides strong support and guarantee for the development of science education.