The wafer carrier structure in semiconductor special device was designed and optimized in this study according to functional requirements of high-temperature heating and low-temperature cooling as well as planeness requirement of vacuum adsorption. The layout of vacuum absorption structure, high-temperature heating unit and low-temperature cooling unit was determined by calculation and simulation. The ultimate structure of wafer carrier was determined through experimental verification. Results showed that surface evenness of this wafer carrier is lower than 30μm in the temperature range of -65 ~ 300 ℃ and it meets the design requirement of temperature fluctuation lower than ± 5℃.