The purpose of the study was to develop a mathematical mechanism which could describe laws of changing electrical signals in nerve fibers in man’s lower extremities and hip prosthesis movement. The article presents a schematic diagram of the bioelectric hip prosthesis control system, main elements of which are an actuator, a control device, and a primary data unit. There are given actual mathematical models of prostheses movement and control signals of man’s central nervous system; on their base was designed the mathematical model controlling bioelectric hip prosthesis movement. A specific feature of the model offered is that the model has a function to characterize a signal transfer from the central nervous system to the actuator of prosthesis. The research results can be applied in the course of hardware and software implementation of bioelectrical prostheses, taking into account physical abilities of the users, creating specific algorithms, studying electric and dynamic characteristics of these devices.