This is a method for producing magnesium sulfate monohydrate from a salt-mixture of sodium chloride and epsomite, in the following ways: the salt-mixture of raw sodium chloride and epsomite is prepared by weight with 545 to 555 portions of salt-mixture, 246 to 256 of water, and 535 to 545 of brine; the mixed material is heated to 74-76 C for the dissolution of the salt-mixture; the un-dissolved NaCl is filtered and the mother liquor is heated to 74-76 C, then evaporated and concentrated and fine grains (magnesium sulfate monohydrate) and rough grains (sodium chloride) are crystallized; after filtration, a mixture of the fine grains and rough grains is obtained; and a standard sieve with 325 mesh is used, at 74-76 C, and the sodium chloride as oversize materials, and the undersize materials are dried at 74-76 C to obtain the magnesium sulfate monohydrate product. The method is easy to operate, has low energy consumption, low production costs, no liquid waste, and no environmental pollution.
