C/SiC composite material bolt was a kind of important fastener that applied in hypersonic vehicles widely.However,the mechanical properties of this material had a relatively large amount of scatter while the distribution pattern still remained in blurry, resulting in significant difficulty in material selection and structure design.In this paper,tensile strength testing experiments were conducted using three kinds of C/SiC composite material bolts (M8,M10,M12) on an electronic-controlled universal testing machine.The probability distribution pattern of tensile strength was obtained.The two-parameter Weibull distribution model was fitted based on the statistical data,and the Kolmogorov-Smirnove test was conducted.The results indicate that the tensile strength distribution of C/SiC composite material bolts accords with the Weibull distribution model,with a characteristic strength β 212 MPa and a shape parameter α 9.45.Moreover,the allowable strength design can be realized based on the present Weibull distribution.