In optimizing the layout design of a multi-product assembly environment, tile analysis of the material flow is a vital ingredient. In flexible assembly systems, assembly time is usually very short thus the transfer time is relatively more important Therefore operations sequence must be so determined, that have no backtracking operations as possible as, It is important to form cells, so that they have no intercell movement in curring much processing delay, and to arrange machines as possible as densly. This study presents a independent cell formation method considering operation sequences and machine capacity in flexible assembly systems.