Abstract: Fertilization is an integral part of the sprinkler irrigation system, and the fertilization method with sprinkler irrigation system provides the most convenient means of supplying nutrients. The hydraulic characateristics of the pressure differential fertilizer injection unit with venturi tube was analyzed, and the change law of the fertilizer concentration in the tank with the fertilizution time was analyzed as well. The uniformity of spraying fertilizer with the sprinkler irrigation system was meassured, meanwhile, based on the results a new type of renovated fertilizer unit was developed and put under operational trial with satisfactory results.