NOVELTY - Co-generation of hydrogen and liquefied natural gas (LNG) includes feeding synthetic ammonia purge gas into ammonia washing tower, countercurrent contacting with water to carry out ammonia absorption, and purifying; feeding into adsorption tower, contacting with molecular sieve adsorbent to obtain dry gas, feeding into liquefaction separation unit of regeneration tower to obtain hydrogen rich gas, and feeding into pressure swing adsorption (PSA) hydrogen extraction unit; and heating, pre-cooling, cooling, feeding into flash tank, separating hydrogen-rich gas.    USE - Method for co-generation of hydrogen and liquefied natural gas (claimed).    ADVANTAGE - The LNG has high purity and methane content of greater than or equal to 98%. The hydrogen has purity of greater than or equal to 99.99%. The method is simple, does not require booster in liquefaction separation step which saves energy, achieves separation of hydrogen and methane, does not need to provide external cooling source, adopts advanced technology of mixed refrigerant cycle which adjusts mixed refrigerant according to different composition and proportion of gas components, and has low energy consumption.    DETAILED DESCRIPTION - Co-generation of hydrogen and liquefied natural gas (LNG) comprises:    (A) feeding synthetic ammonia purge gas into ammonia washing tower bottom part, countercurrent contacting with water from top of tower to carry out ammonia absorption, and purifying to below 200 ppm;    (B) feeding into bottom part of two drying tower comprising adsorption tower and regeneration tower, contacting with molecular sieve adsorbent through adsorption tower to remove water and obtain dry gas, feeding into liquefaction separation unit of regeneration tower to obtain hydrogen rich gas, and feeding into pressure swing adsorption (PSA) hydrogen extraction unit;    (C) feeding into heat exchanger, heating, pre-cooling to - 120 degrees C, cooling to - 155 degrees C, adjusting throttle valve, feeding into flash tank, separating hydrogen-rich gas, returning back to main heat exchanger to return temperature to normal, feeding part of hydrogen-rich gas into the PSA hydrogen extraction unit and another part into dehydration unit as regeneration gas source, feeding liquid effluent from flash tank into distillation column, low-temperature distilling to separate methane, nitrogen and argon, returning back nitrogen and argon into main heat exchanger while discharging liquid methane from bottom of distillation column, cooling to - 160 degrees C, throttling to obtain LNG, and storing through LNG storage tank; and    (D) feeding hydrogen-rich gas from PSA hydrogen extraction unit and dehydration unit into adsorption tower, and subjecting to selective adsorption to remove impurities to obtain greater than 99.99% pure hydrogen.