Effects of Ca(NO3)2 stress on the growth, membrane permeability and antioxidant enzyme activities of cucumber seedlings were investigated. Two cucumber cultivars (Chun 4 and Jinyou 1) were used by sand culture. The results were as follows: relative water content (RWC) of the leaves and roots in two cultivars all decreased when Ca(NO3)2 stress increased. Meanwhile, the membrane permeability, malondialdehyde (MDA) contents and the contents of water-soluble sugar of two cultivars increased significantly with Ca(NO3)2 stress. Whereas the activities of superoxide dismutase (SOD) and peroxidase (POD) in two cultivars increased significantly in low Ca(NO3)2 concentration, and then decreased with the increase of Ca(NO3)2 concentration.