Reliability sensitivity can reflect the influence of the distribution parameter of basic variable on reliability and guide reliability analysis and reliability-based optimization,a non-probabilistic reliability sensitivity analysis method is proposed based on a multidimensional parallelepiped model.The explanation is first given that the non-probabilistic reliability index and the non-probabilistic failure degree are respec-tively used as the reliability measure of structures when the basic variable domain is entirely within and o-verlaps with the safe domain.The analytical expressions of reliability sensitivity of a linear system is then derived,and their application in nonlinear system is further discussed.Three numerical examples are final-ly provided to demonstrate the feasibility and effectiveness of the proposed method.