The invention discloses a steel protection cylinder for bridge collision prevention. The steel protection cylinder comprises a cylinder block; a pulp overflow port is formed in one side of the cylinder block; a blockage plate, matched with the cylinder block, is arranged on the inner side of the cylinder block; a rail, fixedly connected with the inner wall of the cylinder block, is arranged in thecylinder block; the rail is matched with the blockage plate; and the blockage plate slides up and down along the rail to open or close the pulp overflow port. The steel protection cylinder can effectively guarantee the quality of pile top concrete, prevents pollution thereof at the lower part of a pier column, and is safer and more reliable in the blockage process of the pulp overflow port.