The invention relates to a bidirectional non-backstopping overrun clutch. A retainer assembly comprises a retainer outer ring, a retainer inner ring, a spring and a nut. When power is input into a driving end, a clutch outer race, while driving a wedge block to rotate, pushes a roller to move downwards to contact with an inner race, thereby enabling the clutch outer race, the roller and the inner race to engage with each other and then allowing the clutch to transfer torque. When the driving end loses the power, the roller moves to a middle position of the wedge block and thus disengages from the inner race. Regardless of clockwise or counterclockwise rotation of the inner race serving as a driving wheel, the outer race may not be driven to rotate together, i.e., the clutch is in a bidirectional disengaged state. The bidirectional non-backstopping overrun clutch is applicable to various working conditions of a prime mover and a transmission shaft, wide in application range, and steady in engagement, reliable in working, free from noise and simple in structure, and has a great significance for improving the mechanical transfer efficiency of ship power as well as damping and noise reducing.