 This paper proposes a product innovation identification path for enterprises to use when searching for new products based on failed patents. It begins with a functional analysis of the problem to be solved, followed by the extraction of relevant subject matter elements from the core failed patent technology. Next, the trees theory and best worst method are used to generate and evaluate potential innovations. Finally, the feasibility of the path is tested using a case study of a slurry pump. This path provides a practical solution for enterprises to identify product innovation opportunities from failed patents, which can help them to develop more efficient technologies and reduce their costs. This article was authored by Ding Tang Zhang, Xian Wu, Peng Lu, and others.