Abstract: A procurement rescheduling system (20) includes a production planning module (30) for scheduling production and generating production scheduling sheets (102) according to received purchase order modifications (100); a material management module (31) for managing inventory data and bill of material data stored in a database (33); and a procurement rescheduling module (32) for rescheduling material procurement according to the production scheduling sheets. The procurement rescheduling module includes a time span management submodule (321) for managing procurement time spans for different materials, a demand calculation submodule (322) for calculating revised demand for materials in each procurement time span, a delivery date calculation submodule (323) for calculating delivery dates for materials procurement according to the production scheduling sheets, and a material purchase order generating submodule (324) for automatically generating revised material purchase orders.