Abstract:The acidification and salinization in greenhouse soil of different cultivating years of Shouguang City in Shandong province were studied. The results showed that the pH and total salts in greenhouse soil were 6.86 and 2.47g?kg-1, respectively, and the significant acidification and salinizaion were found in greenhouse soil compared with open vegetable soil and natural soil; In two planting periods of 1-12.7a and 12.7-15a of greenhouse soil, the trends of pH values were observed to decrease gradually and then it increased again, but the opposite changing trend with pH was observed for the total salts and the turning point was 8.4a. With the increasing of cultivating years the contents of Na+, Mg2+, Cl-, SO2-4 showed (P＜0.05) to increase gradually and then it had decreasing trends and it had similar trends with the changing trend of the total salts, the change in Na+，Mg2+，Cl-，SO2-4 contents brought about the change for the total salts with the increasing of cultivating years. Studies on salt ions in greenhouse soil indicated that a large part of total salts was accounted by SO2-4、Cl-、Ca2+, the proportions were 62.4%、10.6%、9.3%, respectively. The very significantly correlations were obtained between SO2-4、Cl-、Mg2+、Na + and total salts, However, it was most to SO2-4(r=0.9291)and Mg2+(r=0.7224)among these correlations；The correlation between SO2-4 and pH was very remarkable, and a large accumulation of SO2-4 was one of the important reasons for the acidification in greenhouse soil.