The reflector plays an important role in the optical system. A kind of reflector with orthogonal axis frame is designed, which contains a series of geometric symmetry elements. Its temperature rise and vibration resistance characteristics meet the use requirements. Compared with three common materials, the temperature response and vibration response of the reflector structure are analyzed. The temperature field, thermal stress, mode, equivalent stress and strain of three kinds of reflectors with different material are obtained by using the finite element analysis software ANSYS Workbench. Analysis results show that the temperature response of cast iron HT300 is smaller and its vibration resistance is better, which has a wide application space in the engineering practice of optical system.