Tashan Yan was an irrigation project on the Jin River to the south of today's Ningbo City in East China's Zhejiang Province. The project was built in 833 to fend off tidewater and deposit water in times of drought. Afterwards, the project played an important role in irrigating the nearby field and providing drinking water for the people.

From the Song Dynasty (960-1279) to the Qing Dynasty (1644-1911), the project was revamped for several times.

The irrigation function of the project gradually died out, since most part of it has been buried under sand. It was listed as an important national cultural relic in 1987.