The invention discloses a box body conveying mechanism and a box cover machine. The box body conveying mechanism comprises a second machine frame provided with a second sliding rail, a second moving seat movably arranged on the second sliding rail, a second drive element, a first lifting element installed on the second moving seat, a box body rotating assembly used for receiving a box body of a feeding frame and rotating the box body by 180 degrees and a box body conveying assembly used for receiving and conveying the box body of the box body rotating assembly, wherein the feeding frame is fixed to the upper end of a piston rod. According to the box body conveying mechanism, after the feeding frame receives a box body, under the action of the second drive element, the second moving seat moves to the box body rotating assembly, the box body is conveyed to the position between two first clamping blocks of the box body rotating assembly by the first lifting element, a first clamping air cylinder works, the two first clamping blocks clamp the box body, an overturning motor works to drive an overturning frame to rotate by180 degrees, after the overturning frame reaches the appropriate position, the open end of the box body is downward, and finally the box body conveying assembly receives and conveys the box body of the box body rotating assembly.