The invention belongs to the technical field of elevator safety index detection, and particularly relates to a calibrating method of a balance coefficient detector of a traction driving type elevator. The calibrating method comprises the following steps of measuring the balance coefficient K(0) under the condition of empty load of a car by the elevator balance coefficient detector; respectively loading N groups of test weights Q(weight) onto the car, and respectively measuring the measuring value K(measurement) of the balance coefficient under the condition of each group of test weights by the elevator balance coefficient detector; calculating the theoretical value K(weight) of the balance coefficient under various conditions after the N groups of test weights Q(weight) are loaded onto the car; calculating the difference of the measuring value K(measurement) and the theoretical value K(weight) of the balance coefficient, and taking the absolute value of the difference, so as to obtain the absolute difference K(difference) of the balance coefficient; calculating the geometric average number of K(difference), wherein when the differences are all negative values, the error of indication is expressed as -G; when the differences are all positive values, the error of indication is expressed as +G; when the differences contain negative values and positive values, the error of indication is expressed as +/-G. The calibrating method has the advantage that the potential safety hazards of the elevator caused by inconsistency between the measuring value and the actual value of balance coefficient are eliminated.