Injection-locking solid-state laser is studied to obtain the laser light for 2 μm coherent doppler lidar. Tm,Ho:YLF microchip crystal with both ends coated is used for the master laser. In order to obtain pulse laser, the structure of slave laser is toroidal and an infrared fused silica is used as acousto-optic Q-switch. The master laser as a seed is injected into the slave laser. Via injection-locked and amplification, the single longitudinal-mode and frequency-stabilization pulse 2 μm laser is obtained. A Q-switch output energy is 2 mJ at 20 Hz with a pulse width of 146 ns, and 4 mJ with a pulse width of 86 ns. The wavelength of the output is 2.067 μm. The feasibility is demonstrated that the injection-locking laser is used for 2 μm coherent doppler lidar. The initial optical field in the ring laser is discussed.