The invention relates to the technical field of construction engineering pipelines. A manhole cover is composed of a manhole cover body, a base, pawls, cover opening ejector rods, elliptical reverse thread locking heads, unlocking opening reverse thread rods and the like. A trapezoid stopping ring on the bottom surface of the manhole cover body is sleeved with a pressure-proof rubber ring for preventing noise. When the manhole cover body is installed and placed on the base, the pawls are pressed down by the trapezoid stopping ring, and elastic force of ejector rod springs is transmitted to the pawls through levers and pawl connection rods to abut against and lock the trapezoid stopping ring so that an antitheft effect can be achieved. When the manhole cover body is opened, reverse thread pressure proof rubber plugs, gib headed keys and the elliptical reverse thread locking heads are taken out, the unlocking opening reverse thread rods are screwed into elliptical reverse thread locking holes, conical funnels and conical ejector rods are sleeved and connected, the levers are pushed, and the pawls are receded and unlocked through the pawl connection rods; and at the moment, the levers are just jacked to the upper ends of long-strip-shaped opening unlocking holes, and the manhole cover body is opened in a hidden mode by the pushing force of the unlocking opening reverse thread rods through the levers and the cover opening ejector rods. The contact surface between the manhole cover and a road is increased in a multilayer mode through a pawl mechanism box, a pressure-proof rubber ring flange face and a pavement flange face so that sedimentation can be prevented.