In this paper, we describe a Nd:YLF laser based on high speed RTP electro optical cavity dump ing technique. Two home made 150 W fiber pump modules are used from both sides to pump Nd:YLF crystal. Coupling systems are the key elements in end pumped solid state lasers, the aberrations of which greatly affect the efficiency of the lasers. In order to get high efficient and good quality laser output, the optical soft ware ZEMAX is used to design a four piece coupling system. When the pumped energy is 32 mJ at the repe tition rate of 1 Hz, the output energy is 6.5 mJ with 2.5 ns pulse width. When the pumped energy is 13.1 W at the repetition rate of 200 Hz, the output energy is 2.2 W with small M 2 factor where is 1.04, and is 1.05, and the light light conversion efficiency is up to 16.8%.