In this research, the element of tantalum was chosen to be an alloying element onto the M50 steel by surface alloying in order to improve the high temperature friction properties. Before the surface alloying treatment, the tantalum film was deposited by DC magnetron sputtering. After that, high current pulsed electron beam was used for providing high energy to induce the surface alloying treatment. The microstructrion of alloying layer was investigated by XRD, SEM and TEM. And after the test of high temperature friction, the cross section and wear debris were tested by SEM and EDS. The results reveal that the thickness of surface alloying layer is about 5-6 μm which can be divided into three layers. The aggregation of alloying elements especially Ta contributes to formation of different types of microstructure. The friction coefficient can drop 50% compared to the untreated samples under the environment of high temperature (600 ℃) and heavy load (1.5 GPa). The analysis of wear debris and scratch indicates that the decrease is caused by the formation of oxide with low friction coefficient in the surface alloying layer in process of wear test. It can be concluded that the surface alloying treatment induced by high current pulsed electron beam is a promissing method to declined the friction coeffient at hight temperature.