Absnzict The present paper censiders multi-state systems which are regarded as a generalization of binary systems, and generalizes the concepts ef BW systems proposed by R.E, Barlow and Alexander S.Wu. Since the structure function ef a BW system is defined by using the rninimal path sets of a binary coherent system, the BW system has a strict restriction that the form of mjnimal path sets should be identical for any states of the systern.In this paper we relax the strict cendition and propose a cluss of rnulti-state systems which we call Extended BW systerns (EBW systems). We present some properties of EBW systerns and c!arify the relationship arnong rnulti-state, EBW and binary coherent systems, As the main results ofthis paper, we show that any EBW systems are equiyalent to a class of binAry coherent systerns satisfying some conditions. Furtherrnore, vve proyide the characterization that the class of EBW systems is the maximurn class of the multi-state systems which can be transformed into binary coherent systems whose number is identical to the number of the states of the multi-state systern,