The distribution of the gear temperature field has a significant impact on the gear tooth surface gluing failures,which have a significant impact on the reliability and gear service life. Based on frictional heat between gears meshing tooth surface produced by the asymmetric gear pair with a small teeth number,by using the space gear meshing theory,heat transfer and finite element method are used to analysis of the distribution parameters along the meshing line of frictional heat flow and its impact. The temperature thermal equilibrium equation of the temperature field of asymmetric gear with a small teeth number is established,and the finite element model of the gear pair is built. The frictional heat flows sequentially is loaded on the node unit successively by using ANSYS parametric design language APDL,and the accurate results of gear temperature field are obtained. The results know that,two peak positions of the temperature distribution are in the vicinity of the gear near the top of the tooth and the tooth root. The impact of gear geometry and working parameters on the temperature field changes are analyzed. Increase the displacement coefficient,the addendum sliding speed increasing,resulting in a temperature rise of gear,which provide a reliable basis for the design and optimization of gear lubrication improvement.