In this paper, a modified weld structure of the layered urea reactor has been provided. In the modified structure, new circumferential weld can improve the stress status of the urea reactor. It has the both advantage of separated and integrated layered pressure vessel. This modified design is based on the stress status analysis and the requirement of leak detection. In order to evaluate the modified structure, stresses of original and modified urea reactor shell with interlayer gaps were calculated via Finite element software ANSYS 12.0. The calculation result shows that the maximum stress of the modified structure is reduced obviously in the same condition, and the leak of liner also can be detected effectively.