Abstract: To provide customers with products on time,the Manufacturing Resource Planning(MRPⅡ)systems or Enterprise Resource Planning(ERP)systems are introduced to many manufacturers The Capacity Requirements Planning(CRP)is a basic function of MRPⅡ/ERP systems.But the CRP has some weaknesses.For example,it has no capability to adjust the processes and the work centers when they are out of work or the loads on them are out beyond their capacities,and it is on the hypothesis of infinite capacities when calculating the loads of work centers.The author of this paper presents the concept of adaptable processes set and work centers set for a single step in a material process plan after analyzing the mechanism and algorithm of CRP.A new idea including conditions such as the finite capacities of work centers,the workers and the devices for CRP is puts forward by the author.The author also presents an improved algorithm of CRP that reduces the quantity of calculation.

Key words: MRPⅡ/ERP, Capacity Requirements Planning, work center, condition, algorithm