PURPOSE: A partition structure of an engine water jacket is provided to reduce the piston friction loss and to increase fuel efficiency of the engine. CONSTITUTION: A partition structure of an engine water jacket comprises an upper partition(10), a lower partition(20) and a cutoff wall(30,40). The cutoff wall interlinks the end part of the lower partition and upper partition. The cutoff wall delays the flow of the middle channel. The upper partition and lower partition are formed along the outer circumference. An air bent hole is form on the upper partition and the lower partition.
