Abstract: Venturi Injector is widely used in micro-irrigation system due to its simple structure, easy operation, and needless of electric power. Now most of the Venturi Injector production are copied from abroad ones, and their hydraulic parameters such as suction amount are not very desirable due to the low level of processing methods and technology. In this paper, CFD(Computational Fluid Dynamics) was used to simulate the inner flow field of the Venturi Injector with one factor, two factors and three factors experiment design. The relationships between the structure parameters(i.e., throat length, throat diameter, slot diameter, slot position) and suction amount, and the optimal structure parameters of Venturi Injector were analyzed. Results show that when the inlet pressure and the slot position keep unchanged, the suction amount of Venturi Injector increases with the decrease of throat diameter and length, and the increase of slot diameter; while keep the slot diameter, throat diameter and throat length unchanged, the suction amount of Venturi Injector increases with the increase of inlet pressure; When the slot position move to right, the suction amount and inlet pressure of Venturi Injector decrease. The results can provide theoretic support for dometic Venturi Injector research and development.