The relation of gain coefficient to crystal temperature of quasi-three-level (Tm,Ho)∶YLF laser system was analyzed theoretically,with the conclusion that lower temperature and shorter crystal would reduce the reabsorption loss for lower threshold and high efficiency. A microchip Tm(0.06 in number fraction of atoms),Ho(0.004 in number fraction of atoms)∶YLF laser end-pumped by a continuous-wave laser diode with 2.7 W at 792 nm wavelength was conducted in experiment. Up to 328 mW of output power at 2.06 μm with TEM00 mode was obtained with 1.88 W pumping power onto (Tm,Ho):YLF crystal. The pumping threshold was 450 mW, the slope efficiency of the laser was 22.5% and total optical-optical conversion efficiency was 17.4%. To achieve the optimized condition, the effects of pumping wavelength, polarization direction, crystal temperature on the performance of laser were studied.