Two kinds of tee pipes DN75×75 and DN75×50 were discussed by test methods and numerical simulation. The results showed that local resistance coefficient of main branch to side branch ζ01 and main branch to straight branch ζ02 decreased with increasing Reynolds number and stabilized after the Reynolds number was greater than 1.5×105. The local resistance coefficient ζ01 and ζ02 was correlated with the flow ratio by second order parabolic equations. The numerical simulation results were in good with the experimental data. Through those variables other five kinds of tee pipes were simulated numerically. It showed that the local resistance coefficient ζ01 and ζ02 decreased with increasing diameter ratio, and the variable extent of ζ01 was greater than ζ02. Also the expression equation of local resistance coefficient variation with the flow ratio was given simultaneously. Flow characteristics analysis showed that the main reason caused the local resistance coefficient ζ01 due to the loss of direction changes and velocity distribution caused by centrifugal force, and changes ζ02 was due to the vortex motion and velocity gradient in the straight branch caused by water shearing and transverse circulation in the large flow ratio. 