In general, the damage of the struck ship side is heavier than the one of the striking ship bow in collision of ships. From the point of view of protecting environment and reducing the whole economic loss,the authors consider that the longitudinal stiffness of ship bow should be properly decreased in the precondition that the ship bow is capable of bearing conventional load, so that the probability of breaking of the struck ship side will be decreased. Taking damage mode, collision force,collision force density and energy absorption into account, the authors have studied buffer ship bow constructed of high strength steel. It is discovered that the plate thickness of structure and critical crushing strength of the buffer bow can be reduced in the condition of equal strength. Consequently, the damage of the struck ship side will be reduced.