NOVELTY - Producing beer comprises steeping barley, germinating, drying, removing the roots, and crushing into powder; adding the crushed barley and water into the gelatinization pot, boiling, to obtain soluble malt extract, passing the wort into a separation column and filtering; boiling the resulting wort, adding water, boiling and adding hop; pumping the wort into the precipitation tank, precipitating, cooling; adding beer yeast into the wort, fermenting; pumping the resulting liquid into the aging tank, aging, filtering to further remove residual beer yeast and insoluble proteins.    USE - The method is useful for producing beer (claimed).    ADVANTAGE - The method controls the pollution caused by wastewater, reduces the impact of beer production on the environment, makes full use of the treated water, to achieve water reuse.    DETAILED DESCRIPTION - Producing beer comprises (i) steeping barley, germinating, drying, removing the roots, and crushing into powder; (ii) adding the crushed barley and water into the gelatinization pot, boiling, to obtain soluble malt extract, passing the wort into a separation column and filtering; (iii) washing the gelatinization pot and the separation column, and passing the wastewater into cesspools via pipelines, carrying out ppflow anaerobic sludge blanket and cyclic activated sludge system process, and using the resulting water used in industry and agriculture; (iv) boiling the resulting wort, adding water, boiling for 10 minutes, 30 minutes and each time adding hop before the end of 10 minutes; (v) pumping the wort into the precipitation tank, precipitating, removing unwanted hops and insoluble proteins, and cooling to 7 degrees C; (vi) adding beer yeast into the wort, fermenting in a fermenter at 7-15 degrees C for 8-10 days, and storing for six days; (vii) removing low beer yeast precipitate from the fermentor, pumping the resulting liquid into the aging tank, aging for 7-21 days, filtering to further remove residual beer yeast and insoluble proteins.