By adding rare earth Yb2O3, the superplastic deformation ability of laser weld of TC4 titanium alloy is improved, and the superplastic deformation uniformity of joint is improved. The results show that the addition of Yb2O3 can reduce the flow stress of weld superplastic deformation, improve the elongation and increase the uniform coefficient of joint deformation. With the increase of Yb2O3 content, the longitudinal peak flow stress and elongation of weld first decrease and then increase, and the peak flow stress is 11.9MPa at 6%. The highest elongation was 592.3 %. With the increase of Yb2O3 content in transverse deformation, the joint deformation uniformity coefficient K increases first and then decreases. When the content of Yb2O3 is 6 wt.%, the maximum K value of the sample is 0.209.