A high-purity preparation of mannitol

The present invention discloses a method for preparing a high purity mannitol, the method comprising the steps of: ①1000 molecular nanofiltration; ② reverse osmosis membrane filter; ③ ④ crystallization and recrystallization. The method of preparing high purity mannitol of the present invention is simple in operation, high-purity preparation of mannitol obtained.