The study on reliability of multi-layer structure of thermo-optic switch under thermal mechanical coupling effect is the basic research subject in modern micro-optoelectronics. Power consumption and response time are the most important performance indexes. Based on the generalized thermoelasticity theory, thermo-optic switch models of various structures are built to simulate the temperature and stress field for structure optimization. The numerical results show that an appropriate cross-section shape can reduce the switch power consumption without prejudice to the response speed, the refractive index of the core layer varies with the temperature, and the inter-layer thermal mismatching stress of the double-ridge structure is the maximum. The above findings will introduce new ideas for research and development and design of new optic switches.