The invention provides a water conservancy and hydropower engineering BIM family library construction method, which takes Revit family library construction as guidance and combines the characteristicsof water conservancy and hydropower engineering, and comprises the following steps: step 1, carrying out entity splitting; 2, carrying out model file naming on each split independent part; 3, defining a family category, and before selecting a family sample plate, determining whether the family category belongs to electrical equipment, pipe fittings or mechanical equipment; step 4, manufacturing family parts; step 5, carrying out plane expression setting, which comprises view setting, plane expression, material setting and electromechanical connecting part setting; 6, a family library is established, after family components are manufactured, the quality of the manufactured family components can be distinguished through availability testing and debugging, and finally the debugged family components are classified into the family library; and step 7, applying the family library to the construction technical case, testing compatibility and reusability, debugging according to the satisfaction condition, and finally classifying the debugged family components into the family library.