Abstract: The aggregate used in the roller compacted concrete at Gongguoqiao hydropower station was the excavated material from underground caverns which relied on sandstone and slate.The application of sandstone and slate in roller compacted concrete dam as aggregate was rare, therefore, the mix proportion design combined with the characteristics of excavated material was of great meaning.This paper introduced the design method, experiment process and results, as well as the experience and issues needed further research.