The diode side pump model of solid slab laser is established.The temperature distribution is given out by solving the thermal conduction equation with finite difference method.The absorbed light power and temperature distribution inside the medium with one side-pump and two side-pump are studied respectively.And the influence of pump power on the temperature distribution is also discussed.The results show that homogenous temperature is easier to obtain with two side-pump model and the thermal deformation increases with the increasing pump power.