Abstract: ZOU Yan(about 343-265 B.C.)was a well-known Chinese ancient philosopher and geographer in the Pre-Qin Period. He established two knowledge systems of history and geography. Along with the development of navigation of Qi State, the geographical knowledge about oversea-lands had grown. From this knowledge, ZOU Yan presented a geographical theory of "Nine Large Lands". He thought that China was only a small part of the world. The large land on which China locates was named Chi Xian Shen Zhou, and it was divided into nine parts, called "Nine Lands". There were nine large lands, each of then was the same large as China. The nine large lands made up a division, and there were nine such divisions in the earth. Hence, according to the views of ZOU Yan, there were 81 large lands altogether in the world. All divisions were surrounded by ocean (Da Ying Hai), and in each division the large lands were separated by sea (Pi Hai). ZOU Yan's theory was advanced in Pre-Qin Period, but it was considered an absurd idea in ancient China. Wu Zang Shan Jing(the Classic of the Mountains) is the most concrete and most elegantly written part of Shan Hai Jing. Even though mixed up with some elements of legend and mythology, it is primarily a regional geographic work that contains much realistic knowledge of the ancient times. Concerning the author of Wu Zang Shan Jing, it may be said as opinions varying, and no unanimous can be draw. Synthesizing the relevant factors, this article pointed out that the Wu Zang Shan Jing was possibly written by ZOU Yan and his followers. The reasons included following sections: 1) The academy of Ji Xia and Qi state, in which ZOU Yan being as a chairman once, was the cultural center of China in the Pre-Qin Period. So there were much geographical data, which was from different regions, it is possible for collecting of the Wu Zang Shan Jing. 2) The writing times and contents of the Wu Zang Shan Jing were identical with the activated times of ZOU Yan and his theory. 3) The describing method of the Wu Zang Shan Jing was coincident with ZOU Yan's empiric induction, and the writing style did not show any differences between the Wu Zang Shan Jing and his left literary works.To sum up, being one of the earliest geographers, ZOU Yan should have taken an important position in the history of ancient geography both in China and in the world.