Ancient wooden bridges in China were mainly made of natural wood. Wooden bridge is the earliest bridge form, because it is widely distributed, materials are easy to obtain, and complicated tools are not needed for cutting and processing. The wooden bridge discovered by archaeologists during the Qin Shihuang period is about 300 meters long and 20 meters wide. It is the largest wooden bridge in the world. It has important research value in ancient capital archaeology, especially in the history of bridge construction and traffic in the world, and provides important information for studying Weihe traffic and its changes. Giant wooden bridge in Qin dynasty is located in the northern suburb of Xi, Shaanxi province. It is mainly composed of many huge Woods and some stones. Experts confirmed that this wooden bridge was built to connect the north and south banks of Xianyang, Qin Dou, across the Weihe River. It is an important transportation hub of Xianyang Palace where Qin Shihuang lived and Xingle Palace on the south bank of Weihe River. In fact, the wooden bridge in Qin Dynasty not only played an important role in Qin Shihuang's period, but also continued to the Han Dynasty, becoming an important bridge across the Weihe River in the north of Chang 'an in Han Dynasty. Today, the Weihe River is about 7000 meters away from the place where the wooden bridge was found. On the one hand, the change of Weihe River destroyed Xianyang Palace in Qin Dynasty, on the other hand, it preserved three wooden bridges more than 2,000 years ago. This is an excellent example of studying the relationship between man and nature, which is of great significance to the evolutionary history of human civilization and ecology.