NOVELTY - An energy-saving environmental protection system comprises an underground biomass pool (8), a straw anaerobic methane gas generation device, a domestic sewage purification pool, a solar water heater, a neutralization tower (1), and a raw water tower (2). The straw anaerobic methane gas generation device comprises an anaerobic fermentation tank (4), a gas storage tank (5), and a feed opening (7). The domestic sewage purification pool comprises a pre-treatment pool, and an anaerobic reaction pool.    USE - An energy-saving environmental protection system used for villa-style residence (claimed).    ADVANTAGE - The system recovers straw and domestic sewage; and uses generated methane liquid, methane gas, and methane residue, thus improving utilization ratio of resources and reducing environment pollution.    DETAILED DESCRIPTION - An energy-saving environmental protection system comprises an underground biomass pool (8), a straw anaerobic methane gas generation device, a domestic sewage purification pool, a solar water heater, a neutralization tower (1), and a raw water tower (2). The straw anaerobic methane gas generation device comprises an anaerobic fermentation tank (4), a gas storage tank (5), and a feed opening (7). The domestic sewage purification pool comprises a pre-treatment pool, and an anaerobic reaction pool. A gas outlet of the underground biomass pool communicates with the gas storage tank. The methane liquid outlet of the underground biomass pool communicates with the feed opening. The gas outlet of the gas storage tank communicates with a kitchen range. The underground biomass pool communicates with a down spout of a toilet of a villa-style new residence. A water outlet tube of the domestic sewage purification pool communicates with the neutralization tower. The neutralization tower communicates with the toilet through a pipeline. The raw water tower communicates with a faucet of a kitchen through a pipeline.    DESCRIPTION OF DRAWING(S) - The drawing is a sectional view of the energy-saving environmental protection system.    Neutralization tower (1)    Raw water tower (2)    Anaerobic fermentation tank (4)    Gas storage tank (5)    Feed opening (7)    Underground biomass pool (8)