Planar microspring is a commonly used elastic element in micro-electro-mechanical system (MEMS). In the design and application of planar microspring, the stiffness coefficient of the spring is a very important parameter. The stiffness of the spring The coefficient is determined by the shape, structure, size and material of the spring. Using the energy method of material mechanics, the relationship between the basic structure and shape of the planar micro-spring and its stiffness coefficient is studied to provide theoretical guidance for the design of the planar micro-spring.