The laser properties of laser diode end-pumped (Tm,Ho)∶YLF laser are studied. Based the characteristics of laser diode pumped quasi-three-level system,the energy transfer between Tm 3+ and Ho 3+ is discussed and the rate equations of (Tm,Ho)∶YLF laser are given. The influences of up-coversion effect and reabsorption loss on operation of laser diode pumped (Tm,Ho)∶YLF laser are analyzed theoretically,and the analytical expressions of threshold pump power and slope efficiency are gotten. At the same time, the experiment of (Tm,Ho):YLF microchip laser is conducted, when three crystal is kept at 29 ℃, the threshold pump power is 425 mW, the slope efficiency is 22.5%, the maximum optical-to-optical efficiency is 17.4%, and the relation between the input power and the output power at four different temperature is obtained. The experimental results are in good agreement with theoretical results.