For the Intrinsic Mode Functions solved by the Empirical Mode Decomposition method, the largest Lyapunov exponents of Duffing and Lorenz systems with the Intrinsic Mode Functions lost and cutdown was studied in this paper. It is found that small attractor destruction occurred with the decreasing Intrinsic Mode Functions, but the largest Lyapunov exponent was big. With the low?level Intrinsic Mode Functions lost and cutdown,the largest Lyapunov exponent of the reponse decreased clearly. With the increase of cutdown ratio, the largest Lyapunov exponent decreased more when compared with the original signal.