The subsidence depth of mining equipment and the bearing capacity of deep-sea sediments are important to the design of mining equipment. In this paper, firstly, the subsidence depth model of mining equipment was proposed by using the limit balance theory, according to the deep-sea sediments' physical properties, subsidence, bearing mechanism, and its shear strength changing with depth. Secondly, the bearing capacity of deep-sea sediments is closely related to the subsidence depth of mining equipment. The deep-sea sediment bearing capacity method controlled by subsidence depth was presented on the basis of the subsidence depth model. Finally, the case study and indoor simulation test indicate that the model proposed is reasonable and feasible.