A cutting stroke-adjustable pruning shears is constructed to include a fixed jaw and a movable jaw pivoted together, the movable jaw having an elongated slot and a plurality of retaining notches in one long side of the elongated slot, a holder shell, the holder shell having two parallel side panels pivoted to a middle part of the fixed jaw at two sides and a spine connected between the parallel side panels, a coupling arm, the coupling arm having one end pivoted to the parallel side panels of the holder shell and an opposite end mounted with a pivot coupled to the elongated slot of the movable jaw and selectively positioned in one of the retaining notches, a tension spring disposed inside the holder shell and connected between the holder shell and the coupling arm, and two handles respectively fastened to the fixed jaw and the holder shell.