Some physical and chemical properties including pH, electric conductivity, water soluble total salt and water soluble ions of the greenhouse soil and open field soil in Yixing region were studied. The results indicated the obvious tendencies of acidification and salt accumulation in the greenhouse soil at the 0~20 cm horizon. The main cation was Ca²⁺, accounting for 14% of the total salt content; while the main anions were NO₃^- and SO₄^2-, accounting for 56% and 23% of the total salt content respectively; The greenhouse soil in this region has reached the level of moderate secondary salinization.