Abstract: This paper has established the numerical models of the heat generation from the shoulder,the cylinder shape and the cone shape pins(including pin sideface and endface) during friction stir welding.The effect of pin angle on the heat generation from the cone shape pin has been analyzed.The results confirm that the heat generation from the shoulder and the cone shape pin endface decreases,and the heat generation from the cone shape pin sideface increases when pin angle increases.However,the general heat generation from the cone shape pin decreases firstly,then increases rapidly,with pin angle increasing.