The invention discloses a multiplexing modem of time orthogonal frequency-division, which relates to a modem device with restricted transmitting power, strong anti-frequency offset capability and the performance of resisting inter-symbol interference in the field of communication. The multiplexing modem of the invention comprises components such as a low-medium frequency modulator, a demodulator, an auxiliary multiplexer/demultiplexer, an intermediate frequency amplifier, a D/A converter, a low pass filter, a self-vibration module, a mixer, an adder, a band-pass filter and a power supply, etc.; by adopting TOFDM signals with quasi-constant envelop transmission, the modem of the invention realizes the performance of resisting the inter-symbol interference which is the same as that of the traditional OFDM technology, has the capability of collecting multipath, overcomes the problems of large peak-to-average power ratio and the bad capability of resisting frequency offset, and also realizes the purpose of the multiplexing modem of the time orthogonal frequency-division. The modem of the invention also has the advantages of high integration degree, small volume, light weight and good flexibility, etc. and is especially suitable for the field requiring for the modem with large-capacity wireless data transmission performance among strong multipath high-speed moving targets with seriously restricted power.