The invention provides a wagon coupler unlocking mechanism which comprises the components of a coupler release rod, a release rod base, a supporting base and a coupler release chain. The coupler release rod is arranged on the release rod base and the supporting base and can freely rotate relative to the release rod base and the supporting base. One end of the coupler release chain is rotatably connected with the end of the coupler release rod, and the other end is rotatably connected with a rotating shaft on the wagon coupler. Through rotating the coupler release rod, the coupler release chain is tightened and the rotating shaft on the wagon coupler is driven to rotate, a lock iron block in a wagon coupler chamber is lifted and the wagon lock is in an unlocked state. After the coupler release rod is placed down, the lock iron block falls by means of self weight, and the rotating shaft returns to a locked state, thereby finishing a whole wagon hook unlocking process. The wagon coupler unlocking mechanism has advantages of simple and reliable structure and convenient detachment. The wagon coupler unlocking mechanism can totally satisfy the general requirement and interchange requirement of a railway wagon coupler buffer device in the Commonwealth of the Independent States (CIS), European countries and some African countries. Furthermore wagon utilization efficiency is improved.