Experts have found many Great Wall remains in the territory of Qinghai Province in northwest China after more than two years' field investigation.

The discoveries included a 480-meter-long wall section, 51 beacon towers and 158 pass towers, according to Ren Xiaoyan, a researcher with Qinghai's Archeological Institute.

Construction of many of the remains started in Qin and Han dynasties dating back to some 2,200 years ago and finished in late Qing Dynasty that ended in 1911. Some of them could hardly be identified now due to serious weathering, Shi said.

Qinghai has found 360 kilometers of Great Wall built during Ming Dynasty and the campaign of searching for other Great Wall remains began in 2009.