The invention relates to a manhole cover system with a locker. The manhole cover system comprises a manhole cover, a manhole base, a lock plate, an inner periphery pin, an outer periphery pin, a spring, a key, a lock pin, bolts and the like. When a tooth side of the key matches with the inner periphery pin, a gap between the inner periphery pin and the outer periphery pin is tangent to a projection of the lock plate; the projection is allowed to pass the gap between the inner periphery pin and the outer periphery pin, the key is able to rotate the lock plate to radially retract the pin inwards; accordingly, the manhole cover is opened; or the projection is not allowed to pass the gap between the inner periphery pin and the outer periphery pin, and the lock plate is unable to rotate, so that the manhole cannot be opened. The manhole cover has the advantages that the production materials are widely-ranged, parts are few, production process is simple, the cost is low, the manhole cover is effectively prevented from being stolen, safety of public facilities is increased, and the accident that the manhole traps people is avoided.