The invention relates to a sewage treatment system and a use thereof. The sewage treatment system comprises a reaction device, wherein the reaction device comprises a shell, a separation plate and a buffer container; a treatment space is defined in the shell; the separation plate is arranged in the treatment space to divide the treatment space into a left buffer chamber and a right reaction chamber, the left buffer chamber is provided with an aeration head, the right reaction chamber is provided with an adsorption and separation section and a concentration section from top to bottom, the adsorption and separation section is composed of a movable membrane and activated sludge, a water outlet is formed in the adsorption and separation section, a bottom water inlet and a first air inlet are formed in the left buffer chamber, and a top water inlet and a second air inlet are formed in the adsorption and separation section; the buffer container is provided with a water inlet and a water outlet, the water inlet of the buffer container is connected with the water outlet of the adsorption and separation section, and the water outlet of the buffer container is connected with the top water inlet of the adsorption and separation section. By adopting the system, a carbon source in sewage can be rapidly adsorbed and separated, and the outlet water can be obtained.