Abstract: Cangnan Tiechang Reservoir was a backbone project of the Mazhan Plain low-yielding fields of planning. It mainly designed to flood control, water supply, combined with irrigation and power generation. The dam was designed as masonry arch dam. After the completion of the dam, due to various factors, there were much masonry joints and water-leakage in the vicinity, particularly serious up elevation 89 m. Based on the analysis of geological conditions of the project, core-drilling, underground television and other methods were used to detect diseases of the dam, then a corresponding program of Grouting technology was given. In which drilling and flushing water pressure test were done for filling results detect.