In order to confirm that KTiOAsO4 can be used in optical parametric oscillator (OPO) to generate 2 μm laser, the pulsed 2 μm KTA OPO which uses θ=49°-cut KTA as a nonlinear crystal to generate 2 μm laser light is designed. The oscillation threshold of the OPO is calculated. The signal and idle wavelengths are measured near 2.16 μm and 2.09 μm which are in agreement with theoretical value. And the pulse width is also measured. By using the mirrors whose transmittance are 60%,70％,90％ respectively as the output mirrors of OPO, the output energy and the electro-optic efficiency are detected. And the impact of the reflectivity of output mirror on output energy is tested and the relationship between the output energy and OPO cavity length is got. So the fesibility of using KTA crystal in OPO to generate 2 μm laser light is demonstrated, which can be the theoretical basis for the next research work.