With the establishment of the theoretical model of passive CPT cesium atomic clock, developing simulation analysis and research on the relationship between the CPT signal and the parameters of cesium vapor cell, combined with the method of design and analysis for cesium vapor cell is established while the optimum design parameters are obtained. When the cesium vapor cell is cylindrical, the diameter is 10 mm, the length of cesium vapor cell is 10 mm, the cesium vapor cell operating temperature is 320 K, the buffer gas pressure is 30 torr, the cesium content is 100 μg. With multi-wavelength Doppler absorption spectroscopy experiment and CPT signal lock and frequency stablish test, it is verified that the theoretical model is correct and providing for the method for the design and parameter optimization of high performance Chip-Scale-Atomic-Clock.