To ensure efficient resource collection while minimizing environmental impact, enhancing economic feasibility, and promoting the sustainable development of deep-sea hydraulic mining technology, a hybrid evaluation system was constructed for identifying key influencing factors and optimizing solution selection. Firstly, based on grounded theory, a comprehensive evaluation system was constructed from three dimensions of technology, environment and economy, which includes 5 primary indicators (environmental disturbance, collection efficiency, energy consumption characteristics, structural reliability and collection economy) and their corresponding 20 secondary indicators. Next, the Fuzzy-DEMATEL method and the CRITIC method were applied to determine subjective and objective weights, respectively, followed by comprehensive weighting. Finally, the Pythagorean fuzzy multi-attribute decision-making method based on PFHWD-TOPSIS was used to sort the alternatives and achieve scientific optimization. The results show that the constructed hybrid evaluation system can effectively support factor analysis and scheme decision-making, among which environmental disturbance and economic stability are the key constraint factors in the decision-making of deep-sea hydraulic mining schemes. In the four deep-sea hydraulic mining schemes, the wall-attached jet scheme (C₂) has the optimal comprehensive performance, and performs prominently in terms of environmental disturbance, energy consumption characteristics and economy. The research results can provide a theoretical reference for the optimization of deep-sea hydraulic mining schemes and help the sustainable development of the technology.