The invention discloses a gravity separation and flotation combined sorting device and method. The gravity separation and flotation combined sorting device comprises a device body, a sorting cylinder,a mineralization cylinder, a settlement cone, a coarse-grain sorting cone and a feeding distributor; the device body is of a hollow vertical cylindrical structure; a horizontally-placed connecting cover plate is arranged on the upper portion in the device body, and the device body is connected with the sorting cylinder through the connecting cover plate; a concentrate discharging outlet is formedin the position, on the upper portion of the connecting cover plate, of the device body; an overflow discharging outlet is formed in the position, located below the connecting cover plate and close to the bottom of the connecting cover plate, of the device body; the sorting cylinder is of a cylinder structure; the sorting cylinder is provided with the mineralization cylinder of a cylinder structure, and the mineralization cylinder and the sorting cylinder are coaxially arranged; the lower portion of the device body is connected with the settlement cone, the bottom of the settlement cone is connected with the mineralization cylinder, the bottom of the mineralization cylinder is connected with the coarse-grain sorting cone through a flange, and the coarse-grain sorting cone is coaxially provided with the feeding distributor; and a middling discharging outlet is formed in the bottom side face of the settlement cone, a tailing discharging outlet is formed in the lower side face of the coarse-grain sorting cone, and a feeding inlet is formed in the bottom of the feeding distributor. According to the gravity separation and flotation combined sorting device, the flotation upper limit isincreased, the sorting granularity range is expanded, and thus the recovery rate of coarse particle flotation is increased.