A mechanism that is non-engaging in the forward direction and prevents direction change, comprising a dual ratchet sleeve (1). The dual ratchet sleeve is provided in the axial direction a one-way forward ratchet ring gear and a one-way reverse ratchet ring gear; a pawl base (2), the pawl base being provided with a first pawl (21) and a second pawl (22) capable of moving in a direction perpendicular to the axis of the dual ratchet sleeve; an eccentric drive mechanism (3) for driving the first and second pawl to act, the axis of the eccentric wheel axle (32) of the eccentric drive mechanism being perpendicular to the axis of the dual ratchet sleeve; a tool handle (4) for driving the pawl base to rotate, the tool handle being connected to and fixed on the eccentric wheel (31) or the eccentric wheel axle (32) of the eccentric drive mechanism so as to enable the linkage of the tool handle and the eccentric wheel. The mechanism that is non-engaging in the forward direction and prevents direction change meets the working requirements under multiple states and directly enables torque transmission and state change by means of the handle.