In order to solve thermal effect of laser medium end-pumped by laser diode (LD),a thermal analysis model of YAG-Nd:YAG composite crystal rod with adiabatic end faces,fixed boundary temperature and consecutive heat flow interface was established. A general analytical temperature field expression of YAG-Nd:YAG composite crystal rod end-pumped by super-Gaussian beam was obtained by the methods of eigen-function and constant variation. Meanwhile,some factors,such as the super-Gaussian beam with different spot radius,different orders and the length of YAG crystal,which influenced the temperature distribution of YAG-Nd:YAG composite crystal rod,were quantitatively analyzed. The results showed that when the output power of LD was 50 W,the transmission efficiency of optical focusing coupler was 82%,the maximal temperature rise of the YAG-Nd:YAG composite crystal rod,in which the length of YAG crystal is 1.5 mm,the length of Nd:YAG crystal is 5 mm and the neodymium ion doped concentration in the crystal is 1.0% (mass fraction),end-pumped by the forth super-Gaussian beam was 132.7 ℃. The results would provide a theoretical basis for reducing the thermal effect of laser crystal and reasonably designing thermally stabilized cavity of solid-state laser.