Efficient isomerization of glucose into fructose contributes to the utilization of biomass producing 5-hydroxymethylfurfural (HMF). In this work, we have explored a novel catalyst for isomerization of glucose into fructose. By the mediation of polydopmaine (PDA), MnSn(OH)6 was formed on cryptomelane-type manganese oxide (OMS-2). The composite MnSn(OH)(6)/PDA@OMS-2 can efficiently catalyze the glucose isomerization to fructose, with a yield of fructose 47 +/- 1.6%. When used together with the Bronsted acid catalyst Amberlyst-15, the HMF yield from glucose was 53 +/- 2.5%. Consecutive use of the composite demonstrated that after eight cycles the activity can be retained in terms of the yield of fructose. The mechanism of polydopamine-mediated formation of MnSn(OH)(6) has been investigated. The desired yield of fructose has been obtained by MnSn(OH)(6)/PDA@OMS-2, and the preparation of the catalyst has also shown advantages, including low cost and easy preparation, short preparation time (36 h), and low temperature (<= 70 degrees C).