Conventional scale-setting approach =>Choose the scale Q to be''seemingly"typical momentum transfer = Vary in a certain range, e. g [Q/2, 2Q],[Q/3, 3Q], to discuss its uncertainty Main problems of conventional scale-setting 1)Convergence depends on as-power suppression Once inconvergence appears, one cannot judge whether is its intrinsic property or caused by improper choice of scale 2) By finishing more loop-terms, the scale-dependence could be smaller, it is however caused by cancellation among different orders。Conventional scale-setting approach =>“Choose” the scale Q to be ``seemingly” typical momentum transfer =>“Vary” in a certain range, e.g. [Q/2, 2Q], [Q/3, 3Q], to discuss its uncertainty Main problems of conventional scale-setting 1) Convergence depends on s -power suppression； Once inconvergence appears, one cannot judge whether it is its intrinsic property or caused by improper choice of scale。 2) By finishing more loop-terms, the scale-dependence could be smaller, it is however caused by cancellation among different orders