In this paper,a practical impulsive lag synchronization scheme for different chaotic systems with parametric uncertainties is proposed.By virtue of the new definition of synchronization and the theory of impulsive differential equations,some new and less conservative sufficient conditions are established to guarantee that the error dynamics can converge to a predetermined level.The idea and approach developed in this paper can provide a more practical framework for the synchronization between identical and different chaotic systems in parameter perturbation circumstances.Simulation results finally demonstrate the effectiveness of the method.