The invention discloses a crimping machine upper mold height adjustment device, system and method. The device comprises at least one adjustment sheet group. The adjustment sheet group includes a plurality of adjustment sheets. Each adjustment sheet is a flat object or a block with certain thickness. The adjustment sheets are combined into different heights to assist in the adjustment of the upper mold height of a crimping machine, and the thinnest adjustment sheet is used for satisfying the requirement for adjustment precision. The thickest adjustment sheet in the adjustment sheet group can be selected according to the required maximum height, and the thinnest adjustment sheet in the adjustment sheet group can be selected according to the required precision. The invention can solve the technical problems that a conventional upper mold height adjustment method can only be used for rough adjustment of the upper mold height due to inaccurate height datum, the adjustment process is complex, the number of times of adjustment is too many, and the adjustment precision is too low.