Abstract: Aiming at the practical application problems of droppable ballast device, we carry out the optimization and research of droppable ballast device on the "Jiaolong" manned submersible based on ergonomics principle. The device is designed according to ergonomics standard, and computer-aided design technologies are used in the design. The whole process of analyzing, planning, and designing of droppable ballast device optimization will play an active role in inspring the ergonomics analysis and design of marine technologies and equipment.