Abstract The model of driving Lorenz systems is examined in the case that there are some parameter differences between the drive system and the response system. It is found that the strict synchronization does not exist although the parameter difference is small. We also explore the dynamic behaviors of a stable laser system driven by the chaotic signal, and we show that there is no synchronization between the drive and the response. However, this leads to the concepts of driving two subsystems with the chaotic signal, and leads to the synchronization among the subsystems. We apply these ideas to the laser subsystems,and the synchronization of the two laser subsystems, which are of different parameters and driven by the x component of the Lorenz system, is presented.