This paper describes a control strategy for a vertical jumping motion of the jumping robot. The target system consists of 4-link and 3-actuator, which is a model of human body. This system is fullactuate in initial states, but in the process of jumping, this system becomes underactuate. Besides, constraints of the system are variable in the process. Therefore, this system is an underactuated and a variable constraint system. In this paper, the control method which overcomes the difficulties is proposed. Furthermore, by considering properties of a vertical jumping motion of human, the proposed control method realizes a humanlike vertical jumping.