The 45 degrees beam splitting mirror plays a vital role on image quality in the Holographic system, in order to study the influence of environment temperature variation on the 45 degrees beam splitting mirror in the Holographic system, finite element analysis method is used to simulate the anti-three through seven mirror deformation at 27 degrees C, 28 degrees C and 29 degrees C temperature in theory. A new real-time monitoring and displaying photoelectric system for ambient temperature and beam splitting mirror distortion detection is designed to provide real-time temperature change and deformation detection, which is made up of laser speckle interferometer, chip temperature sensor, two-operational amplifier, MCU and LED indicator. And the out-plane displacement value measured in the experiment under the condition of temperature correspondingly are 406nm, 420nm and 427 nm. Finally, the relation equation of temperature and mirror deformation is established by the method of exponential equation fitting, which will provide preliminary theoretical and experimental reference for further research.