Shuanghe cave is a superlarge karst cave system developed in the dolomite formation of Middle—Upper Cambrian Loushanguan Group, which is currently the longest dolostone cave in the world. Study on formation of the cave is helpful for the program of Shuanghe Cave World Geopark declaration. In previous works, only a few researches focused on the formation and evolution of the cave. And those discussions were all on the basis of scale and shape of the karst cave. Here, the authors aim to investigate the formation and evolution of Shuanghe cave system through geological field surveys and laboratory analysis.Field observations were carried both on surface and in karst caves. We measured a geological section from Huahuazi to Jiaozishan. In the laboratory, we got the chemical indexes of surface water and groundwater. Based on the field investigation, strike directions of joints and cave tunnels are counted up and compared. It is found that in the dolomite formation, dissolution of syngenetic anhydrite and gypsum is crucial to promote and develop erosion phenomenon. And the lithologic characters and structures controlled the directions and shapes of the karst caves. Calcite saturation indexes (SIc) and dolomite saturation indexes (SId) are negative numbers for most of surface water and groundwater on this area, which indicates those unsaturated water provided main geological power for formation of the caves. According to the research results, authors put forward the evolution model of Shuanghe cave system. The model show that formation of the karst caves had experienced a series of geological processes from pore, isolated hole, connected cave, large karst cave, until multilayer karst cave group.