The characteristics and application scopes of RMR method, Q system and HC method are analyzed. The surrounding rock of the underground powerhouse of CCS hydropower station in Ecuador is classified by RMR method, Q system and HC method respectively, and the classification results are compared. Expert experience is used to make comprehensive evaluation on the surrounding rock of the underground powerhouse, which has already been classified on basis of RMR method, Q system and HC method respectively, and the final classification of the surrounding rock of each section of the underground powerhouse is obtained. The study result shows that there is little difference among the classification results of these three methods and that HC method, which has been widely used in China, is applicable to projects in foreign countries and is worth to be further promoted to projects abroad.