Abstract: The effects of secondary phases on stress corrosion property of friction stir welded (FSW) seam of 7A52 aluminum alloy were investigated with SEM-EDS during low stress rate test (SSRT). The experimental results indicate that the stress corrosion cracking (SCC) occurred on the retreating side of HAZ in FSW seam in 3. 5% NaCl solution. The fracture position was corresponding to the position of minimum microhardness value in FSW seam. The SCC susceptibility of FSW seam was highest at strain rate of 1×10^{- 6} s^-1 and lowest at 1×10^-5 s^-1. Different secondary phases had different effects on the initiation and growth of stress corrosion cracks. Al9Fe0.84Mn2.16Si easily induced the initiation and growth of cracks,however,the pitting resulted from the dissolved Mg₂Si could only initiate small cracks.