The invention provides an active ship-collision preventing device of a bridge. The active ship-collision preventing device comprises struts fixedly mounted on the left and right sides of a bridge pier, each strut is provided with a spring buffer device in the middle and is connected with a rolling shaft at the other end, and each rolling shaft is connected with a leather collar. By the arrangement, the problems that an existing collision preventing device occupying navigation areas is unsatisfactory in collision preventing and energy absorbing effect and cannot prevent a nose from piercing damages in civil engineering bridge collision preventing design are solved.