Abstract: The effects of boron on some enzyme activity and root paramaters of rape (Brassica Juncea) cultivars under water and soil cultural conditions were studied. The main results obtained were summarized as follows: At B-deficiency level, the activity of superoxide dismutase and catalase in rape leaves was decresed and activity of peroxidase and glacose- 6- phosphate dehydrogenase increased, but there was signifficantly difference between the B-deficience and B treatment of sensitive cultivar, and there was no signifficantly difference between the two treatments of non-sensitive one. The inhibition of B-deficiency on the length, weight, volume, surfuce area, active absorption area and active absoption area ratio of sensitive cuitivar was more severe than nonsensitive one.