With information entropy theory, the fuzzy static intensity and fuzzy load of conjunction bolt will be equivalent to the stochastic static intensity and the stochastic load, respectively. The static intensity reliable index according to conjunction bolt safety grade is determined. With the reliable index, the design method of conjunction bolt static strength is established, and the reliability safety factor of the static strength is obtained. The research results show that:1) Regarding security rating for general, relatively important and important conjunction bolts, the reliable indexes of yield intensity are 0.815,1.920and 3.819, respectively; and the reliable indexes of bolt tensile strength are 3.740,4.729and 6.820, respectively. 2) Based on the reliable index which satisfiyes the conjunction bolt static intensity, regarding security rating for general, relatively important and important conjunction bolts and under static load condition, the smallest reliable safety factors of yield strength are 1.10,1.25and 1.45respectively; the smallest reliable safety factors of tensile strength are 1.35,1.50and 1.60, respectively. Under changing load condition, the smallest reliable safety factors of yield strength are 1.15,1.35and 1.75, respectively; the smallest reliable safety factors of tensile strength are 1.60,1.80and 2.20, respectively.