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 and digital chaotic systems 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 .