In this paper, we investigated the technical problem of the recovery of overlength and heavy load conveying booms of self-unloading ships. A method of folding the conveying boom with a hydraulic-four-bar mechanism is presented, and by using a mathematical model for the optimization of folding speed stationary with ADAMS software, the optimization data and results were obtained. The multi-objective optimization index is introduced, and the multi-objective optimization problem is discussed. The results of the multi-objective optimization showed that parameters such as angular velocity and the change of angular acceleration of the conveyor boom were optimized. The paper has manufactured the connecting rod mechanism, and developed the self-discharging folding conveyance equipment. Through practical application, we determined that the developed folding conveying equipment had the advantages of smooth movement and high folding efficiency.