The invention relates to a self-counter flow type horizontal shaft tidal current energy power generation device. The self-counter flow type horizontal shaft tidal current energy power generation device comprises an impeller generator unit and a self-counter flow device. The self-counter flow device comprises a turntable bearing, a box, a bearing end cover, a movable sealing structure, a connecting disc, a conduction slip ring, a support and a base. The impeller generator unit is directly fixed to the base through the support. The inner ring of the turntable bearing is fixedly connected with the box. The outer ring of the turntable bearing is connected with the large end face of the top of the connecting disc. One end of the box is connected with the impeller generator unit, and the other end of the box is connected with the bearing end cover. The movable sealing structure is installed in a groove of the bearing end cover. The small end face of the connecting disc is connected with the support, and the lower end of the connecting disc is fixedly connected with the base. The conduction slip ring is installed inside the connecting disc. A movable ring wire of the conduction slip ring is connected with the impeller generator unit. A fixed ring wire of the conduction slip ring penetrates the base and is connected with a shoreside bus. The self-counter flow type horizontal shaft tidal current energy power generation device can effectively solve the reversing problem of a tidal current energy power generation water turbine, high power generation efficiency is achieved, and vibration, noise and maintaining cost of the unit are effectively reduced.