In the article ,several most typical optical switches such as optical wave-guide switch ,bubble switch , thermo-capil-lary optical switch and thermally actuated MEMS optical switch ,etc. and the micro themal problems involved were compre-hensively reviewed. Based on an in depth discussion on the key mechanisms ,several possible strategies for solving the above issues were proposed. This is expected to provide a valuable reference for further designing new optical switches and improving the currently existing optical switches.