The experimental research on effects of different levels of nitrogen fertilizer on productivity of and nitrate residues in NS-Cross cabbage planted in winter 2013 at Quang Vinh ward, Thai Nguyen city shows that: the growth and productivity of this plant are significantly affected by the different levels of urea fertilization, in which it has the highest productivity when using 160 kg Nitrogen fertilizer per hectare but the nitrate residue exceeds the allowed index. It therefore does not satisfy the safety vegetables standards. On the other hand, the yield is good' with 263.78 quintals per hectare when using 140 kg of Nitrogen fertilizer per hectare and nitrate residues index is under the allowed threshold of residue.