The temperature field of a pulsed laser diode (LD) end-pumped Yb:YAG crystal with variable thermal conductivity is studied. A thermal conduction model with heat-insulted end faces and constant peripheral temperature is built. Based on the semi-analytical theory and by means of Newton′s method, the temperature field distribution of the crystal is obtained. The influences of pump power, super-Gaussian order, spot radius, and crystal size on the temperature field are analyzed. The calculation results show that, when the crystal is pumped by a pulsed LD with super-Gaussian order of three, pump power of 80 W, and radius of 400 μm, and under the condition that the thermal-conductivity is constant or non-constant, the maximum temperature increase at the pumped end faces is 31.69 and 35.66 ℃, respectively. The research results provide certain theoretical guidance to the design of lasers.