T800 alloy is a good wear-resistant coating material for tip shrouds of turbine blades operated at high temperature. In order to make clear the best serving state of T800 alloy, microstructure and high-temperature fretting wear behavior of T800 alloy in casting and cladding state were studied. During welding, alloying elements of K417G alloy substrate diffused into welding melting pool, which resulted in that there was a decrease in the alloying elements of the T800 clad. Laves phases were dissolved completely and then precipitated to form fine Laves phases in matrix during solidification. As a result, as-cast T800 possessed larger volume fraction and size of Laves phases, higher hardness and high-temperature fretting wear resistance than T800 cladding