The invention mainly belongs to the technical field of diesel engine air intake and exhaust systems, and particularly relates to a high performance marine diesel engine cylinder cover. The high performance marine diesel engine cylinder cover comprises a cylinder cover body, the cylinder cover body is internally provided with an air inlet channel and an exhaust channel, the air inlet channel comprises a long air inlet channel and a short air inlet channel, the long air inlet channel is the channel between an inlet of the long air inlet channel and an outlet of the long air inlet channel, the short air inlet channel is the channel between an inlet of the short air inlet channel and an outlet of the short air inlet channel, the long air inlet channel communicates with the short air inlet channel through a cavity structure, the cavity structure is a stable pressure cavity, the air inlet of the long air inflow channel is tangential, and air inflow of the short air inlet channel is screw-type. An eddy is formed after air inflow passes an inside spiral air channel, an outside tangential air channel to the eddy merges into a larger eddy, thus mixing capacity of air inflow and fuel spray ofa diesel engine is improved, deformation of a novel structure with a circular lower part and a square upper part is small when pretightening force is applied, and cylinder cover sealing performance is ensured.