The end deformation,which is one of the thermal lens of the diode pumped Nd∶YAG is discussed by computer simulation with two different pumped light profile.First of all,Nd∶YAG′s heat model and theory model are built up,then the temperature field is calculated.Under the define condition,the deformation′s distribution is plotted and the focal lens of the end deformation are known.And the experiment aims at a further a study of the thermal effects caused by the end deformation.