Abstract: In this paper tee diffuser discharge wastewater is presented.The mathematical model and calculational method are used to predict the flow phenomenon of tee diffuser discharge.The developments of the centerline velocity,concentration and dilution are calculated.The length of the main current core,the transverse velocity and concentration are given.The kinetic energy of discharge and the length of tee diffuser are found to have strong influence on the characteristics of tee multiport diffusers.