There are valleys formed by alluvial rivers in the mountains of southwest Zhejiang. The ancient built weirs on the rivers to irrigate and live, forming many ancient weir irrigation districts. This article takes ancient weir irrigation districts in Bihu Plain as the research object and understands it as a bottom-up layered system composite the natural basis landscape system, the landscape of water conservancy system, the agricultural settlement landscape and the water conservancy management mechanism from the perspective of landscape architecture. Through literature interpretation, data analysis and on-site investigation, it is analyzed that the construction of water conservancy projects and transportation in these districts have a certain impact on the site selection, spatial form and distribution of farmland of human settlements. By studying the construction wisdom of ancient weir irrigation districts in Bihu Plain, it can be used for reference to protect the local landscape, spatial pattern and water heritage of the ancient irrigation district.