The utility model discloses an economizer that is arranged in hydrogen manufacturing to become gas cooling system, including well changes gas / feed gas heat exchanger, well change gas air cooler, well change gas water cooler, first pre -heater and second pre -heater, well change gas come the pipeline in order the material channel through the media channel of well change gas / feed gas heat exchanger, well change gas air cooler become change gas output pipeline in the material channel connection of gas water cooler in and, the feed gas comes the pipeline to connect feed gas output pipeline through the well material channel who becomes the gas / material channel of feed gas heat exchanger, the material channel of first pre -heater and second pre -heater in order. The utility model relates to a rationally, simple structure, cheap cost, the practicality is strong. Becoming gas excess heat in the further utilization of this device, giving raw materials air stripping temperature, low circulating water use amount falls in the temperature of change gas in reducing simultaneously, can reduce raw materials air preheater's steam quantity simultaneously, realizes energy saving and consumption reduction's purpose.