The invention discloses a device for improving the content of maltitol and a preparation method thereof. The device comprises a saccharifying tank. A feeding port and an emptying port are formed in the upper end of the saccharifying tank, a timer and a pH display are installed on the outer side of the saccharifying tank, and a discharge port is formed in the lower portion of the saccharifying tank. By installing a heating device, a thermometer and the pH display, the combination can improve the temperature requirements for all steps, real-time display is achieved, and the inner states of the saccharifying tank are known and changed in time. The steps such as syrup liquifying and saccharifying are conducted, and the DE value is detected for many times in the saccharifying process of syrup, so that the saccharifying process in the saccharifying tank can be known, and the saccharifying time and the saccharifying enzyme quantity can be contrasted through figures; and the best saccharifying time and the saccharifying enzyme addictive quantity can be chosen, the effects that saccharifying is maximized, and the composite reaction is not serious are achieved, and the content of a maltitol finished product is increased.