Abstract: The thermal effect of a laser optical system will affect the transmission of the light and the use of laser. To study the influence of thermal effect of the laser optical system, the finite element analysis software of ANSYS was used to build a thermal-stress analysis about single emitter laser unit module system in this paper. The thermal characteristics of the device corresponding for different output powers were studied, and the optical properties of optical device was analyzed by the software of Matlab using Zernike polynomial further. Results show that the main aberration of optical element under the influence of thermal is astigmatism, which provides a guidance for design of aberration compensation mode later.