Abstract: The dam location of Mianhuatan hydropower station shows symmetrical cross-strait terrain, with high and steep mountain and narrow river, where there has RCC gravity dam whose height is more than hundred's meters. Underground houses are in the left bank. Dam foundation's main engineering geological problems are: dam foundation stability against sliding, leakage of dam foundation and high slope on both sides, etc. This article mainly introduces engineering treatnent measures for engineering geological problems, which would be a reference for similar project.