Abstract: To acquire high efficiency middle wave infrared(MWIR) laser of 3 m~5 m，the high repetition rate driving electro-optic Q-switched synchronization technology and LD side-pumped technology were used to get high repetition rate laser output with 1.06 m narrow width. Periodically poled lithium tantalate (PPLT) was pumped to achieve highpower MWIR laser output of 3 m ~5 m. As the input current was 20 A and the Q-switched frequency was 10kHz, the 1.06 m laser with 15 W power was obtained. After pumping PPLT by the laser, the 3.9 m laser with maximum power of 2.6 W was got. The conversion efficiency from 1.06 m to 3.9 m was 17.3%. Experiment results indicate that the high repetition rate driving electro-optical Q-switched technology and LD side-pumped technology can be used to obtain high-repetition narrow-width 1.06 m polarized laser, and pumping PPLT can obtain high-power highefficiency 3.9 m MWIR laser.