As a pump source,1565nm pumping band can efficiently diminish the loss of manifold fast non-radiative decay and upconversion losses compared to 800nm and 1180nm bands.Theoretical model of Tm3+∶Ho3+ co-doped silica fiber for 2μm laser pumped at 1565nm laser is established.After the comprehensive rate equations and propagation equations are given,characteristics of the system in steady state at hypothesis situation are analyzed by using numerical simulation way.As high as 1.7W laser output power was achieved with a slope efficiency of 67% and quantum efficiency of 57% when the pump power is 3W and fiber length is 2.2m.Numerical simulation results indicate better capability of the fiber and higher conversion efficiency as far as we know.