The invention provides a method for calibrating the empty roll gaps of a sheet and strip cold-rolling mill. The sheet and strip cold-rolling mill comprises at least two mill frames or a single frame respectively with an upper working roll and a lower working roll which can be adjusted if necessary. The method comprises the following steps: step one: the frame lifts up rolls to the top; step two: the rolls are preliminarily calibrated: opening a roll gap, applying contact rolling force to enable the roll gap to be closed, gradually overlaying delta T1 down-pressing inclination in the direction reverse to the inclination direction of the roll gap, executing step four when the detected rolling force deviation is within the allowable range; executing step three when the inclination direction of the roll gap is changed when being compared with the previous time; and suspending roll calibration when the repeated times exceed the allowable maximum times n max; step three: the rolls are fine calibrated: in the inclination direction of the roll gap, gradually reducing down-pressing inclination delta Ti, wherein the i being more than or equal to 2, the i belongs to N, and executing step four when the detected rolling force deviation is within the allowable range; and step four: roll calibration is ended.