The invention discloses a bottom structure of a container ship with bottom longitudinal girders centrally arranged. The bottom structure comprises an outer bottom plate and an inner bottom plate whichare arranged from bottom to top. A plurality of containers are arranged on the upper end surface of the inner bottom plate, and the multiple containers are fixed to the inner bottom plate through a plurality of box legs arranged on the inner bottom plate in a penereating mode at equal intervals, longitudinal ribs are arranged at the multiple box legs on the lower end surface of the inner bottom plate at equal intervals, the outer bottom plate is provided with a plurality of longitudinal ribs with upper positions and lower positions corresponding to the longitudinal ribs disposed on the lowerend surface of the inner bottom plate, and the multiple longitudinal ribs are arranged in parallel with the center line of the breadth; a plurality of heavy-type bottom longitudinal girders are arranged on the upper end surface of the outer bottom plate laterally; a plurality of light-weight bottom longitudinal girders are arranged between the heavy-type bottom longitudinal girders parallelly; anda plurality of solid rib plates are arranged on the upper end surface of the outer bottom plate longitudinally. The bottom structure for the container ship can increase bottom modulus margin and enhance bottom stiffness through the longitudinal girders disposed near a midship area at intervals and the solid rib plates arranged near a shipboard area, and has the advantages that the cost is cost and the strength is high.