Based on fuzzy Petri nets, a fuzzy reasoning Petri nets (FRPN) model is defined. And then, combining fuzzy Petri nets with matrix operation, an algorithm of formalized fuzzy reasoning process is proposed. Based on the fuzziness and uncertainness of the knowledge in the disassembly process of products, a decision making model in disassembly process is established. Furthermore, taking realistic disassembly as an example, an algorithm of decision-making in disassembly sequence is discussed. The result shows that the model of decision-making has strong parallel operation ability in the disassembly process sequence. It also can make intelligent decisions based on the product information originating from each disassembly step.