Abstract: As important indexes to measure the mechanical properties of engineering structures, strength and stiffness have always been the focus of attention in the field of engineering optimization. In addition, the uncertainty factors existing in service process of engineering structures also have a great impact on structural performance. To ensure the reliability of stress and compliance of the continuum structure under uncertain loads, a polynomial chaos expansion-based reliability design optimization method is proposed. The Kieisselmeier-Steinhauser function is used to aggregate the maximum stress and compliance to construct the limit state function of the structure. The polynomial chaos expansion is introduced to establish an explicit surrogate model of the limit state function with respect to the random load variables, simplifying the derivation process of the target performance function with respect to the random variables in reliability analysis. The derivatives of the target performance function with respect to the design variables are derived, and the method of moving asymptote is used to update the design variables. Finally, two typical cases and Monte Carlo simulations are performed to verify the effectiveness of the proposed method. The numerical results show that the proposed method can provide a design that meets both stress and compliance reliability requirements.