MEMS stoppers are commonly used structures to prevent failures caused by mechanical overload such as shock and pressure. However, the numerical research of the stoppers could be computationally costly and non-convergent, since it involves non-linear mechanical features such as contact and collision. This poses difficulties to the reliability design and optimization of MEMS. This paper proposes a parametric model of MEMS stoppers that is computationally efficient for reliability design. Reliability analysis and optimization of typical stopper structures are conducted base on the model we proposed.