In order to solve the problem of thermal expansion coefficient (CTE) mismatch failure of a large-size CLCC device after 100 times,-45 ℃~85 ℃ temperature cycling tests, two optimization schemes were proposed to improve the CTE mismatch, and the simulation comparison analysis was carried out. Based on the improved scheme, the fatigue life was calculated by finite element simulation and Engelmaier model, and the temperature cycling test was completed. The simulation results showed that the CTE mismatch between alumina ceramics, solder and FR4 substrate could be understood better by using the lead with proper brazing parameters in the middle of ceramic, which could meet the practical requirements. This study had a reference value for the design of large size alumina ceramic package.