As a new type of material,the cement sand and gravel (CSG) has the characteristics of low cost and easy construction, so it has been widely applied in many aspects of cofferdam and retaining dam.This article mainly expounded the application of CSG as basis filling material in Alagou ditch reservoir spillway, and made a detailed introduction from raw materials selection, CSG mixture, paving and rolling to quality monitor and control.The result can provide a reference for the application of CSG material in hydraulic engineering.