This paper investigates the synchronization of two Newton-Leipnik
Chaotic Systems. A new sufficient condition of global asymptotic synchronization is
attained from the theory of stability of time-varying systems. In addition , compared
with the previously proposed method , the sufficient condition for the
synchronization of two linearly coupled unified chaotic systems is simpler and less
conservative , and the range of coupled coefficients is wider. Numerical simulation
shows the effectiveness and feasibility of this method.