Abstract: A truncation model is presented for the fuzzy variable with the non-closed membership function. And the fuzzy strength variable and fuzzy stress variable are truncated in engineering application. The general failure probability distribution is established based on the truncated membership function, and the numerical algorithm for general fuzzy-random failure probability is given. Both the fuzziness and the randomness of the basic variable and the state variable are considered in the present method. The combination of the high strength fuzzy set and the high stress fuzzy set is illustrated and the rationality of the present model is verified. The present combination ap- proach can be extended to the structure with multiple fuzzy variables, laying down the theoretical base for engi- neering application.