A system for reducing a content of 5-hydroxymethylfurfural in a high fructose syrup, comprising: an ion exchange positive column and an ion exchange negative column for performing cation and anion removals in sequence for an F42 high fructose syrup; a heat exchanger for performing heat exchange and temperature reduction for an F55 high fructose syrup; a mixed bed column for performing purification for the heat-exchanged F55 high fructose syrup; and an evaporation tank for performing concentration for the F55 high fructose syrup subjected to mixed bed treatment, characterized in that the heat exchanger comprises: a first heat exchanger and a second heat exchanger connected in series, the first heat exchanger and the second heat exchanger comprise a first inlet, a second inlet, a first outlet and a second outlet respectively, the F55 high fructose syrup enters the first heat exchanger through the first inlet of the first heat exchanger and then goes out of the first outlet of the first heat exchanger, and then enters the second heat exchanger through the first inlet of the second heat exchanger and then goes out of the first outlet of the second heat exchanger and then enters a liquid inlet of the mixed bed column through a liquid inlet pipe, the F55 high fructose syrup purified by the mixed bed column enters a second inlet of the first heat exchanger through an outlet of the mixed bed column, and then goes out of the second outlet of the first heat exchanger and then enters a liquid inlet of the evaporation tank, the second inlet of the second heat exchanger is in communication with cooling water through a water inlet pipe, and the heat-exchanged cooling water goes out of a second outlet of the second heat exchanger. an ion exchange positive column and an ion exchange negative column for performing cation and anion removals in sequence for an F42 high fructose syrup; a heat exchanger for performing heat exchange and temperature reduction for an F55 high fructose syrup; a mixed bed column for performing purification for the heat-exchanged F55 high fructose syrup; and an evaporation tank for performing concentration for the F55 high fructose syrup subjected to mixed bed treatment, characterized in that the heat exchanger comprises: a first heat exchanger and a second heat exchanger connected in series, the first heat exchanger and the second heat exchanger comprise a first inlet, a second inlet, a first outlet and a second outlet respectively, the F55 high fructose syrup enters the first heat exchanger through the first inlet of the first heat exchanger and then goes out of the first outlet of the first heat exchanger, and then enters the second heat exchanger through the first inlet of the second heat exchanger and then goes out of the first outlet of the second heat exchanger and then enters a liquid inlet of the mixed bed column through a liquid inlet pipe, the F55 high fructose syrup purified by the mixed bed column enters a second inlet of the first heat exchanger through an outlet of the mixed bed column, and then goes out of the second outlet of the first heat exchanger and then enters a liquid inlet of the evaporation tank, the second inlet of the second heat exchanger is in communication with cooling water through a water inlet pipe, and the heat-exchanged cooling water goes out of a second outlet of the second heat exchanger.