A wireless passive microwave temperature sensor based on Complementary Split Ring Resonators (CSRR) is designed to meet the requirements of surface temperature measurement in harsh environment. The existing wireless sensor devices, due to their size parameters and high temperature performance constraints, can not meet the test requirements. In view of the above problems, attempted to use High-Frequency Structure Simulator (HFSS) electromagnetic design simulation software to simulate and optimize the different structure sizes of wireless passive sensor and to study the quality factors under different conditions, the high temperature simulation test of the sensor is completed at 25~1 200 degrees Celsius to get the optimized product structure. At the same time, the main factors that affect the sensor performance and corresponding relationship are also studied.