Abstract: In order to simplify the process of compaction test, shorten the test cycle, improve the work efficiency, it chooses 123 soil compaction test data of hydropower engineering projects of Gaobeidian, Xingtai, Shijiazhuang and other places in Hebei province for statistical analysis, and gets the soil liquid limit and the optimum moisture content, the linear regression equation of the optimum moisture content and maximum dry density. Then the applicability of the linear regression equation is proved by an example.