The potential application of 2 μm laser is introduced. A 793 nm fiber-coupled laser diode is used to end pump TmYAP laser. A high efficient and 1990 nm laser at room temperature is obtained. 933 mW output power is attained at 1990 nm when pumping power is 4.5 W. The optical-to-optical efficiency is 27%, and the slope efficiency is 37%. The influencing factors of the laser output are also analysed, such as the curve radius of output mirror, the output transmission and the length of the laser resonator.