Abstract: In order to explore the effect laws of jet nozzle geometric parameters on self-priming performance of flow-ejecting self-priming spray, the jet nozzle geometric parameters including total length L1, nozzle angle θ, outlet length L2 and outlet diameter D2 were designed as changed factors, and 9 kinds of different jet nozzles were developed. The rules of two gas and liquid phase flow rate of the pump, impeller inlet velocity, gas phase volume distribution of outlet and internal gas phase volume distribution of the impellers for 9 kinds of different jet nozzle geometric parameters during the self-priming process were obtained by numerical simulation based on L9(34) orthogonal test. The analysis results showed that the order of the jet nozzle geometric parameters affecting the two gas and liquid phase flow rate of the pump was D2>L2>L1>θ, and the order of the jet nozzle geometric parameters affecting the impeller inlet velocity was L2>θ>D2>L1, the order of the jet nozzle geometric parameters affecting the gas phase volume distribution of impeller inlet was θ>L1>D2>L2, the order of the jet nozzle geometric parameters affecting the gas phase volume distribution of the impeller was D2>θ>L1>L2. Optimization results showed that the best combination of the jet nozzle geometric parameters was as follows: total length L1=55 mm, nozzle angle θ=42°, outlet length L2=2 mm and outlet diameterD2=13 mm. The study provides a reference for the design of flow-ejecting self-priming spray pumps.