This paper describes briefly the basic principles for analysing lithologyand coal quality with the optimized scale transformation method, and discus-ses tentatively important technical parameters in logging objective function,convergence criteria in iterative solution process and initial iterative valueswith a suite of principles for their selection put forward. Based on calculati-ons for changing some technical parameters, we have analysed and comparedmajor technical indices (such as convergence rate) of some important scaletransformation methods, and advanced the best scale transformation methodfor analysing lithology and coal quality. In addition, a discussion is made onsome troubles that might occur in conducting such analysis with the scaletransformation method, with the means for overcoming these troubles sugge-sted.