Abstract: The section of weld was simplified as isosceles trapezoid.ANSYS software was used to simulate the residual stress field in TC4 titanium alloy plate with variable time step method.The effects of volume and shape of weld on welding residual stress distribution were studied while the volume was controlled by the trapezoid median and the shape by the angle of the trapezoid leg with respect to the vertical direction.It is showed that,for a constant volume,the maximum equivalent residual stress increases with the increase in the taper of weld,and increases sharply when θ is more than 6.5°,but for a constant taper,the maximum equivalent residual stress decreases with the increase in the volume of the weld,and decreases slowly and smoothly when d is less than 1.5 mm.The results can provide a reference for optimizing welding parameters.