Three cytoplasmic male sterile lines(CMS)and their maintainer lines of the nonheading Chinese cabbage〔Brassica campestris L.ssp.chinensis（L.）Makino var.communis Tsen et Lee〕.were taken as experimental materials,and the contents of chlorophyll,soluble sugar,soluble protein,proline and changes of the activities of SOD,POD,CAT in leaf were tested during seedling.The results showed that the contents of chlorophyll,soluble sugar,soluble protein,proline in CMS were significant lower than their maintainer,while the activities of three protective enzymes(SOD,POD and CAT)were higher in CMS with the treatment of low temperature stress.The contents of chlorophyll and soluble protein decreased continuously in both CMS and their maintainer;while the contents of soluble sugar,praline and the activities of three protective enzymes(SOD,POD and CAT)at first increased,then decreased under cold-stress.There was consistency in all stages of change between CMS and its maintainer line.And after processing,the differences in physiological and biochemical characteristics reduced.All these facts suggested the resistance of cold stress of non-heading Chinese cabbage OguCMS was greatly improved.