The invention discloses a code multiplexing differential chaotic modulator-demodulator for integrated code subscript modulation and relates to modulation and demodulation in a communication system. The code multiplexing differential chaos modulator-demodulator comprises a modulator and a demodulator. The modulator comprises a binary/decimal converter, a serial/parallel converter, a natural number/combinatorial number mapper, a Walsh code selection controller, a chaotic signal generator, Q+1 Walsh code generators, a multiplier, a time delay unit, a shift switch and an adder. The combinatorial comprises a receiver, a multiplier, a square wave generator, an accumulator, an absolute value resolver, a comparison and selection controller, the shift switch, a decision device, the natural number/combinatorial number mapper and the binary/decimal converter. Transmitted information bits are mapped on selection of a Walsh code, a transmission data rate is improved, the bandwidth is increased, the energy efficiency is improved, and the bit error rate performance under an AWGN channel and a multi-path Rayleigh fading channel is equal to or better than that under conventional DCSK (Differential Chaotic Shift Keying). The modulator-demodulator is competitive in a short-distance communication application.