Abstract: To find the best water-manure supply method of reducing nitrate content without affecting biomass of Brassica campestris L., and provide reference for the economic and environmental fertilizing method with low nitrate residue, the effect of different EC value nutrient solutions on the biomass, soakage and nitrate content of B. campestris L. was studied. The results showed that in the 10 days of field setting, the concentration of nutrient solution rarely influenced the physical indexes. After 10 days, the physical indexes increased with the increase of nutrient solution concentration below 2.4 dS/m, and it had no significant effect on fresh weight when the concentration was higher than or equal to 2.4 dS/m. The nitrate content obviously increased in harvest time when EC value was more than or equal to 2.4 dS/m. The water absorbing ability of B. campestris L. was positively correlated with the concentration of nutrient solution, and water use efficiency reached the highest under nutrient solution concentration of 2.4 dS/m. The best culture condition is: 1.2 dS/m in the first 10 days of field setting and then 2.4 dS/m instead.