Abstract: During the service of pressure vessels, a variety of structural damage will occur, among which the corrosion pit formed by the corrosion of the loaded materials is the most important defect. In addition, cracks are formed due to the stress concentration in the pit position, which may propagate and result in fracturing and leakage. Stress intensity factor, as an important parameter to characterize the cracks, is widely used in engineering to judge the safety and reliability of the mechanical structures. Thereby, with reference to the two-parameter pit-crack model, the change rule of the nominal stress intensity factor of crack in the presence of pit-crack was discussed with ANSYS finite element software. The results show that the existence of pit-crack increases the nominal stress intensity factor of crack, but the effect decreases with the increase of pit-crack spacing and trends to be stable. Moreover, the effects of the pit parameters and the length-depth ratio of cracks on the stress intensity factor have obvious interval characteristics. Generally, the research results could provide reference for the failure evaluation of pressure vessels with pit-cracks.