Abstract: The stress of P92 steel elbow with spherical defects was analyzed. According to the functional relationship between the maximum equivalent stress of spherical defects and wall thickness and circumferential angle, the prediction equation of the defect maximum stress of the elbow with axial section of 15°-85° was established. The results show that different axial sections had little effect on the stress of spherical defects, and the stress was more concentrated in the inner arc side of the elbow, and the stress decreased with the increase of the distance between the defect and the inner wall.