Abstract: According to the relevant technical specifications for water conservancy and hydropower construction and safety regulations, the authors put forward the water conservancy and hydropower engineering major hazard source analysis matrix method. We first find the dangerous source of water conservancy construction process by LEC method, then use the AHP method combined with the expert evaluation method of quantitative analysis of dangerous source, eventually get the safety index to determine whether a construction process or operation is a major risk source. Finally, analyzes the risk of pressure pipeline construction of Dagangshan hydropower station using the method.