Abstract: In the design work of seaward sewage discharge project, it's an effective means that adopt the method of combing the numerical simulation with the model test.Based on the project of discharging sewage, this paper simulated the sewage discharge diffuser with help the of network model of HydroInfo-1D, obtaining the values of flow rate, flow velocity and the Froude number of each nozzles, and then designed the process of hydraulic model test to validate the results of numerical simulation.According to the simulation results, the diffuser nozzle flow showed good uniformity under two kinds of design conditions, all the Froude number of the nozzle are greater than 1, it meets with the qualification and requirements of the design specification.In addition, through comparing the actual experimental results with the calculation results, the maximum error of the calculated flow and the experimental flow are 2.18 percent and 2.42 percent respectively, the maximum error of the calculated velocity and the experimental velocity are 2.19 percent and 2.43 percent respectively, it indicated that the calculation results of the model has a higher precision rate than experimental results.The results of this study shows that this model can simulate the sewage sea diffuser with great accuracy, and the design parameters of pipeline meet the requirements of practical operation.