Continuous wave Tm∶YAP solid laser at 2 μm using laser-diode end pumping is reported. In the experiment, five kinds of the pump source of different spot energy distribution were selected, maximum 20.9 W 2 μm laser output was realized ,light-light conversion efficiency was 26.1%, slope efficiency was 39%.We found the spot energy distribution in relationship with optical-optical conversion efficiency and maximum power output by comparing five kinds of the pump source of different spot energy distribution,so that the ideal pump source will be selected quickly in future experiments.