It is very serious of blade wear of twist bit to drill hard-to-cut materials, while the blade wear is the main wear form of twist bit. Aimed at using the electric hot drilling to test hard-to-cut materials as stainless steel plate, the relationship between the grades of the blade wear from parameters such as feeding, heating current and cutting speed to twist drill were analyzed quantitatively. At meanwhile the influence tendency of the blade wear to surface roughness of hole-wall is also researched.