In this research, the possibility of motor-spring series connection type biomimetic actuator was investigated. The motion of the joint angle is controlled by two D.C. motor through each spring. The actuator has one powered joint (knee) and two free joints (ankle and hip). The both free joints of the actuator was attached to the spline shaft. The control method how to make jumping and soft landing by this actuator was investigated. The optimal continuous jumping sequence was investigated based on the optimal sequence of bending and stretching jumping. It is necessary to make the landing posture during the "in the air" term. Direction reversing timing have to be adjusted by the previous jumping height. The both of the mathematical simulation and the experimental results show that this optimal scheme increase the jumping hight.