Abstract: The SMA490 BW weathering steel cross welded joints were ground in different ways. The effects of different grinding methods on fatigue properties of SMA490 BW weathering steel cross welded joints were studied,and the fatigue fracture morphology was studied by SEM.ABAQUS finite element software was used to calculate the stress distribution and stress concentration coefficient of cross welded joints. The results showed that the fatigue limit of unground specimens was about 70. 6 MPa,that of simple ground specimens was about 98. 6 MPa,and that of transition arc ground specimens was about 104. 4 MPa. The fatigue limit of simple ground specimens and transition arc ground specimens was 39. 7% and 47. 9% higher than that of unground specimens,respectively. The stress concentration coefficients of unground,simple ground and transition arc ground toe were 1. 558,1. 402 and 1. 297,respectively. The stress concentration coefficient of simple ground and transition arc ground was reduced by 10. 0% and 16. 8%,respectively.