The invention discloses a system and process for fluorine-circulation magnesium removal of sulfate solution. The process includes: step one, magnesium removal, to be more specific, adding a fluoride serving as a magnesium removal agent into magnesium-containing sulfate solution, filtering a reaction product, and performing liquid-solid separation, wherein filter residue is magnesium fluoride; steptwo, defluorination, to be more specific, adding a calcium-containing fluorine removal agent into zinc sulfate solution subjected to magnesium removal, filtering a reaction product, and performing liquid-solid separation, wherein filter residue is calcium fluoride; step three, magnesium fluoride conversion, to be more specific, subjecting sulfuric acid and magnesium fluoride generated in the stepone to co-heating reaction in a reaction tank, absorbing hydrogen fluoride by water to obtain hydrofluoric acid, cooling the solution to crystallize, separating out magnesium sulfate crystal, neutralizing obtained hydrofluoric acid by a metal oxide to obtain fluoride solution, and returning the fluoride solution obtained in reaction to the step one to serve as the magnesium removal agent. Therefore, the process realizes fluorine recycling, so that treatment cost is sharply reduced.