Abstract: In view of the performance of the spreading sequences for spread-spectrum communication system, a novel method of obtaining chaotic digital sequences based on the extended chaotic map is given in this paper. The correlation and balance performances of the new sequences are analysed, furthermore, an advanced method of generating the digital sequences is proposed, in order to get excellent balance performance. The simulation results show that the chaotic spreading sequences generated by the advanced method possess excellent performance and security, specially for CDMA communication system.