During hydropower project construction, various construction conflicts and interference pose different effects on the quality, safety and schedule of the project. In particular, the relations among period, space, and facilities of large-scale group construction are much more complicated. In order to analyze and solve these problems, we introduce the concept of space-time collision detection into hydropower engineering construction by integrating the 4D simulation and collision detection functions in BIM (Building Information Model), and propose the implementation methods and procedures of collision detection. We apply the space-time collision detection method to engineering projects like cavern group excavation and large-scale construction equipment installation and operation, and propose early warning and solutions to possible conflicts in the process of construction.