Abstract: With dynamical servo control theory introduced,life-like brachiation control of underactuated two-link robot is studied.For the life-like brachiation control of underactuated two-link robot,the dynamical servo theory is introduced to solve the problem of tracking a given trajectory by the terminal of swing arm.According to the pendulum-like features of primate's brachiation,a feedback control law is designed based on Lyapunov stability theory,and then the singular point in the closed loop system and their influence on the system's convergence ability are analyzed.The experiment results on a physical underactuated two-link robot show the effectiveness of the designed control strategy.