The utility model provides a membrane separation device for extraction and concentration of soybean small peptides, belonging to a production device for soybean small peptides. The membrane separation device comprises a hydrolyzer, the upper end of the hydrolyzer is provided with a feed hole, a discharge hole at the lower end is connected with an inlet of a transfer pump, a stirrer in the hydrolyzer is connected with an output shaft of a speed reducer on the hydrolyzer, an outlet of the transfer pump is connected with a feed hole on a filter, a discharge hole at the bottom of the filter is connected with an inlet of a transfer pump, an outlet of the transfer pump is connected with a concentrated solution tank, an outlet of the concentrated solution tank is connected with an inlet of a high-pressure pump, an outlet of the high-pressure pump is connected with an inlet of a protective filter, and an outlet of the protective filter is connected with an inlet of an ultrafiltration membrane device. The membrane separation device adopts the ultrafiltration membrane for separation, which is a non-heating separation method and has the characteristics of no phase transition, low energy consumption, high separating efficiency, simple structure and stable production.