Abstract: The stress concentration, inhere relationship between geometrical structure parameters and fracture forms in C/SiC riveting joints were investigated by FEM and experimental validation. The results show that the cone angle has little influence on the stress concentration, but it has important influence on stress value. The suitable cone angle range is 2°-10°. The critical radius of C/SiC rivet is 2.2016 mm by simulations. The rivet will break when the radius of C/SiC rivet is smaller than 2.2016 mm. Otherwise, the rivet will be pulled out of SiC. The critical radius of C/SiC rivet is 2.25 mm by experiment. The error between simulation result and experimental result is 2.2%, which validates the established FEM models for analyzing the stress concentration and fracture forms and the stimulation results.