Abstract: A 1.54 m laser was obtained using periodically poled lithium tantalate (PPLT) crystal pumped by 1.06 m laser. Intracavity optical parametric oscillator(OPO) was adopted and parameters of resonant cavity were optimized by using V-type cavity. The change of the beam spot along with the thermal focus length of gain medium and the impact of the angle of V-type cavity on beam quality were analyzed. As the input electric power was about 100 W, the 1.54 m laser with the repetition rate of 10 kHz, pulsewidth of 125 ns and average power of 1.9 W was acquired, and the electro-optical efficiency of 1.9% was achieved.