This paper consider the dynamics and a problem of controlling chaos in a nonlinear electromechanical system which consists of the van der Pol oscillator coupled to the Duffing oscillator. The stability of the critical points is analyzed using the analytic Routh-Hurwitz criterion. And adaptive backstepping design is used to control the electromechanical system with six parameters unknown. Finally, give some numerical simulation studies of the system in order to verify the analytic results.