A signal pulse with the 1566nm central wavelength is presented by use of a noncritically phase-matched KTP2OPO pumped by 1. 06μm laser. When the pump energy is 100mJ, the output energy is 31. 9mJ and the relevant conversion efficiency is 30. 9%. The signal pulse width (10ns) is narrower than the pump pulse width (30ns) ,When the internal angle is changed from 90°to 80°, the signal tuning range is from 1566~1596nm.