Smoke temperature distribution in non-smoke evacuation under different mechanical smoke exhaust rates of semi-transverse tunnel fire were studied by FDS numerical simulation in this paper. The effect of fire heat release rate (10MW 20MW and 30MW) and exhaust rate (from 0 to 160m3/s) on the maximum smoke temperature in non-smoke evacuation region was discussed. Results show that the maximum smoke temperature in non-smoke evacuation region decreased with smoke exhaust rate. Plug-holing was observed below the smoke vent when smoke exhaust rate increased to a certain value. Smoke spreading distance can be divided into three stages according to changes of smoke exhaust rate. The maximum smoke temperature model concluded that the peak temperature rise at tunnel vault is proportional to 0.75 power of dimensionless fire power. The maximum temperature in non-smoke evacuation region decays exponentially with the increase of smoke exhaust rate. However smoke vent interval influences the dimensionless maximum temperature in non-smoke evacuation region slightly. Smoke vent interval influences the dimensionless maximum temperature in non-smoke evacuation region slightly.