To seek for effect of water and fertilizer coupling on celery,with 3 factors(N,P,W) and 5 levels(factors levels including-1.682,-1,0,1,1.682) of the secondary regression of orthogonal block design,artificial water control experiments in the shed of rain-free condition were conducted in semiarid cold region of northwest of Hebei to study effect of water and fertilizer coupling on nitrate content of celery.Results showed that irrigation quantity was the chiefly factor to affect nitrate content of celery,phosphorus quantity was the secondly factor,nitrogen quantity was the thirdly factor.Based on the public heath index,nitrate effect was the better in the condition of middle level water and fertilizer,but which was the lowest in low level water and low fertilizer,on which was between the two in high level water and high fertilizer.The effect order of interaction was phosphorus and water coupling>nitrogen and water coupling>nitrogen and phosphorus coupling.In the water and fertilizer management strategy,the value interval of the three factors was the same to the different nitrate content interval,which indicated the substituting effect among the factors.It was a mostly feasible condition to the middle level water and fertilizer from the public heath index.