Experiment investigation of windage heat on straight tooth and slant tooth of labyrinth seals composed of three teeth and two cavities with honeycomb bush and smooth bush had been made to study the effect of rotating speed and the pressure ratio of inlet to outlet and structure of tooth and bush.The results show that the total temperature of leakage fluid caused by windage heat may be neglected at low rotor speed and is increased with the increasing rotation speed between 3000r/min and 6000r/min.The total temperature ratio of first tooth to all teeth is more than 50% with smooth bush and is only 20% with honeycomb bush under low pressure ratio and enhanced to 50% with the increase of the pressure ratio.The straight tooth show increased windage heat when compared to slant tooth with the same bush due to the larger extension length of seal surface curve.