An L shaped micro spring was designed and fabricated based on MEMS technology. According to the analysis based on classical material mechanics theory, it showed that the max stress inside the micro spring was 88.75 MPa when the force of 10 mN was acting in the vertical direction, which was located in the connection part. The finite element simulation showed that the max stress was 89.326 MPa under the same condition, which was quite consistent with the theoretical analysis. The micro spring tensile experiment was carried out with Tytron250 tester system. The experiment result showed that the fracture position of L shaped micro spring was located in the connection part, which proved the correctness of the theory and simulation. On this basis, the effective way to improve the performance reliability of the micro spring is to increase the width of the connection part of the micro spring.