基于瞬态热传导方程，通过积分变换方法求解得到脉冲高斯光束双端抽运Tm:YAG棒的时变温度场解析表达式，进而求得时变热焦距。同时定量模拟，分析了不同抽运功率、重复频率与占空比对脉冲激光二极管双端抽运Tm:YAG棒轴向瞬态温度分布和时变热焦距的影响。模拟结果表明：随着脉冲抽运个数的增加，Tm:YAG晶体棒内温度和热焦距整体均呈锯齿状分布，并最终趋于稳定的周期性分布；随着抽运功率、重复频率与占空比的增加，Tm:YAG晶体棒整体温度升高，且棒两端面中心点与棒轴向中心点温差增大，而时变热焦距整体逐渐变短且波动范围变小。研究成果为进一步研究热效应补偿和谐振腔设计提供了理论依据。

Based on transient heat conduction equation, pulse Gaussian beam dual-end pumped Tm:YAG rod time-varying temperature field analytical expression and the time-varying thermal focal length are obtained by the integral transform method. The effects of pumping power, repetition frequency and duty ratio on pulse laser diode dual-end pumped Tm:YAG rod axial transient temperature distribution and the time-varying thermal focal length are quantitatively analysed. Simulation results show that with the increase of pulse number, the temperature distribution and the thermal focal length of Tm:YAG crystal rod appear jagged and eventually get to the periodic distributions. As the increase of pumping power, repetition rate and duty ratio, the whole temperature of Tm:YAG crystal rod increases and the temperature difference between the Tm:YAG rod on both ends of the center and the axis center of rod becomes larger, while the time-varying thermal focal length gradually becomes shorter and the fluctuation range is smaller. The results provide theoretical basis for the further study of heating compensation and cavity design.