The invention relates to a low-pressure methanol synthesizing process. In the low-pressure methanol synthesizing process, both a primary reactor and a secondary reactor adopt a boiler feed water forced circulating heat transfer technology, heat transfer is fast and efficient, the device layout can be effectively simplified, the project investment of a device frame is reduced, and the problems of circulating ratio decrease, a non-ideal heat effect and the like, which are caused by inaccurate calculation of the layout height of a steam pocket, do not appear; through forced circulation, the circulating ratio can be effectively increased, reaction heat can be efficiently and reasonably utilized, and the heat transfer effect is enhanced; a jumper wire is arranged between an outlet of a synthetic gas compressor and an inlet of the secondary reactor, so that stable operation of catalysts in the two stages of reactors in different stages of the service life is achieved, and through the jumper wire, loads of the reactors are conveniently and forcibly adjusted, so that the production ratio of medium-pressure steam to low-pressure steam is flexibly adjusted; a connection position of fresh synthetic gas is arranged behind a synthetic gas thermostat, so that the heat transfer area and the specification of the synthetic gas thermostat can be reduced and the project investment is reduced.