During the Warring States period, a large number of roofs were covered with blue tiles; Compared with the Western Zhou Dynasty, the firmness and color of slab tiles and pipe tiles, as well as the decorative patterns on semi-circular tiles, have made remarkable progress. Besides decorative strips, there are square bricks and hollow bricks. The circular tiles in Qin and Han Dynasties had sparse and diverse patterns. Many adobe and hollow bricks are printed with patterns. From the Warring States, the Western Han Dynasty to the Eastern Han Dynasty, the structure of tombs gradually developed from hollow brick beams to arch coupons and vaults at the top, which solved the problems of anti-corrosion and compression that wooden tombs could not solve since the Shang Dynasty. At that time, in addition to ordinary bricks, arch coupons also used special wedge bricks and tongue-and-groove bricks. The way of issuing coupons is either single-layer coupons or double-layer and multi-layer coupons. Each layer of vouchers often has a layer of sleeper bricks, which are called "volts". This method of alternating coupons and volts was later widely used by brick coupons and stone coupons. However, at this time, the masonry mortar has not been mixed with lime. In building construction, brick materials are mostly used for abutment and roof, and sometimes they are also used for sticking walls or strengthening walls.