To solve the problems of single fishing object, insufficient reverse-circulation energy and low debris recovery rate of existing local reverse-circulation fishing tools, a new local reverse-circulation fishing tool, which integrates collection and fishing, is proposed. The flow field of the tool is simulated by computational fluid dynamics (CFD), and the mechanism of reverse-circulation formation of the tool is revealed, on the basis of which the numerical simulation of the tool structure optimization is carried out. The results show that the reverse-circulation system is formed by the entrainment of the high pressure water jet formed by the nozzle, and the performance of the tool can be improved by increasing the number of nozzles appropriately. The performance of the local reverse-circulation fishing tool increases first and then decreases with the increase of the nozzle diameter, and further increasing the nozzle diameter results in the failure to form an effective reverse-circulation system. The change of nozzle geometry affects the performance of the local reverse-circulation fishing tool, which is the best with a conical nozzle, but the required displacement is relatively large. The research results can provide reference for the optimization design of local reverse-circulation fishing tools and theoretical guidance for the on-site operation of local reverse-circulation fishing tools.