The present paper describes briefly the principles and instruments of theultrasonic imaging loggng method, a new loggng means recently developed incoalfield exploration. The typical images and curves selected from data of tensof boreholes show that, when applied to coalfield exploration, this method notonly possesses the functions of other logging methods, but can play a specialrole in the interpretation of such geologic phenomena as joints, bedding, fissu-res and other small-sized structures, nodules in coal layers and deformation ofhanging walls and bottom walls.