Abstract: The residual stress distribution of coiled tubing in the process of ERW welding, weld heat treatment and overall heat treatment were simulated initially with the finite element method. The results show that welding residual stress distributing around the weld and the residual stress value is higher in the weld center. It was much lower in other parts of the tube. The maximum residual stress value was 592 MPa. Welding residual stress decreased after the weld heat treatment process and the overall heat treatment process. The maximum residual stress value was 452 MPa after the weld heat treatment process and it was 275 MPa after the overall heat treatment process. This showed that heat treatment processes can effectively reduce welding residual stress.