The components of the flux are optimized and the environmental friendly flux with excellent comprehensive performance is prepared. Then the composition of the solder paste is optimized to prepare the SMT environmental protection and high efficient lead-free solder paste, and its performance is studied. The results show that the storage stability, printability, weldability and environmental protection of the SMT environmental protection and high efficient lead-free solder paste are good, and the reliability is high. The related technical indexes have reached or superior to the commercial solder paste, and have reached the commercial level initially.