Adaptive multiple impedance control based on passivity is studied about two robot manipulators cooperating an object which interacts with external environment actively. The dynamic model is derived by Newton-Euler equation and the relations between the forces are analyzed. The relations between stiffness coefficient and convergence are explained by solving the differential equation when the stiffness coefficient is known. The adaptive impedance controller based on passivity is designed combining adaptive control and generalized impedance control when the stiffness coefficient is unknown. The impedance control based on internal force is adopted for the cooperative system. The simulation results prove the validity of the method.