In this paper, a multi-segment bonded crystal model of YAG/Tm:YAG/ YAG/Tm:YAG/YAG structure is proposed firstly and the thermal effect of LD double-end pumped multi-segment bonded Tm:YAG crystal is investigated. The thermal distribution is simulated and the thermal focal length of the multi-segment bonding is calculated and measured, which confirms that it can effectively alleviate the thermal effect. In experiment, when the absorbed power is 26 W the laser with a center wavelength of 2014.52 nm and an output power of 8.27 W is obtained, simultaneously optical-to-optical conversion efficiency is 31.8% and the slope efficiency is 38%. •In this paper, a multi-segment bonded crystal model of YAG/Tm:YAG/ YAG/Tm:YAG/YAG structure is proposed firstly and the thermal effect of LD double-end pumped multi-segment bonded Tm:YAG crystal is investigated.•The thermal distribution is simulated and the thermal focal length of the multi-segment bonding is calculated and measured, which confirms that it can effectively alleviate the thermal effect.•In experiment, when the absorbed power is 26 W, the laser with a center wavelength of 2014.52 nm and an output power of 8.27 W is obtained, simultaneously optical-to-optical conversion efficiency is 31.8% and the slope efficiency is 38%.