An acoustic emission technique was developed to study the tribological characteristic of boriding SKD steel using a pin-on-disk type wear testing machine with acoustic emission sensor. AE signal of 300 kHz frequency spectrum generated by crack propagation in the specimens was observed in the wear tesing. The R. M. S. value of the emission signal was expressed in terms of wear and friction parameters, The experimental results showed that AE generation from pin contact with a rotating disk indicates the feasibility of utilizing AE in boriding metal wear sensing.