Abstract: Field experiment of Fertilizer is a very important factor in soil testing fertilization.It also can obtain useful results about optimal dosages of fertilizer,time and method of supplying fertilizer.This studied will establish the optimal mode in planting caster and promote the cultivation system with high yield from field experiment.The conclusion is the yield observably increase with supplying nitrogenous fertilizer.The relativity is y =-0.2278x2＋5.1452x＋220.59,R2=0.6675.The appropriate dosages of nitrogenous fertilizer is 12kg/667m2 for planting castor in Ningxia Yellow River Irrigation Area.The same result as Phosphor.The relativity is y=-1.3618x2＋19.403x＋180.89,R2=0.8908,The appropriate dosages of phosphor is 8kg/667m2。