The characteristics of the critical equipment of the deep-sea mining vessel have been illustrated through the description of the mining operation process based on the large-scale scientific research project of the deep-sea mining vessels. The design of the strengthening structure is analyzed according to the appropriate specifications based on the critical equipment of A-frame crane and tower. Several optimization schemes are proposed for the optimization and comparison of the structural design in order to find out the optimization methods to reduce the local stress. It can provide references and methods for the structural strength design of ships.