A system and method for generating analog-digital mixed chaotic signal and an encryption communication method thereof are provided. In the system and method, the complementarity between continuous chaotic systems (12, 22) and digital chaotic systems (11, 21) are reasonably utilized. In specific, the digital chaotic systems, which are separated from each other, control the local continuous chaotic systems respectively, so as to enable the continuous chaotic systems, which are also separated from each other, to stably and synchronously work for a long time. Thus, there is no need to transmit the synchronizing signal, and as a result the anti-attack capability is increased effectively. Further, the continuous chaotic systems disturb the local digital chaotic systems to prevent the digital chaotic systems from degradation. This compensates the drawbacks of digital chaotic systems.