Abstract: This paper proposes a mixed probability-interval uncertainty model considering correlation and a structural reliability analysis method which can solve problems of relevant variables. First, relevant angles of probability variables, probability-interval variables and interval variables are defined respectively in order to quantitatively describe the correlation between variables. Then through affine coordinates relevant variables are transformed into independent variables. A reliability analysis model is put forward, and a highly efficient method is built to solve the reliability index and failure probability interval. Finally two numerical examples are provided to verify the validity of the method.