An order management system and method for automated logistics based on-demand box supplying is disclosed. The system pre-estimates a dimension required by all of the merchandise according to an order data, and selects a sheet material according to the size to form a finished container. The dimension of the unfolded sheet material before folding into the finished container is quite small. In terms of warehouse space utilization, a space required by a single finished and folded box is able to stack dozens of sheet materials, so that the warehousing efficiency is greatly improved. By integrating with a box folding module and a sealing module, fully automated logistics can be achieved with human intervention.