A slide rail mechanism includes a rail member, a first supporting frame, a second supporting frame, a bracket and a reinforcing member. The first supporting frame is movable relative to the rail member. The second supporting frame is movable relative to the first supporting member. The bracket and the second supporting frame are movable relative to each other. The reinforcing member is movable relative to the rail member in response to movement of the first supporting frame. Wherein, the rail member includes a first engaging structure, and the reinforcing member includes a second engaging structure. The reinforcing member is configured to be engaged with the first engaging structure through the second engaging structure.