The invention discloses an optical transmission device based on direct-sequence-spread-spectrum time-division-multiple-access, which includes a signal transmitting module and a signal receiving module. The transmitting module is connected with the receiving module by optical fibers. The transmitting module is used for receiving an external data sequence signal, encoding the external data sequence signal into a direct-sequence-spread-spectrum time-division-multiple-access electric signal and modulating the resulting electric signal into corresponding spread-spectrum optical signal for transmission by optical fibre. The receiving module is used for receiving the direct-sequence-spread-spectrum time-division-multiple-access optical signal, and sequentially performing photoelectric conversion, analog despreading, analog-digital conversion and clock recovery to obtain the external data sequence signal. The invention realizes direct-sequence-spread-spectrum modulation supporting direct detection; at a receiving end, the despreading in analog domain removes impairments and improves sensitivity. The interleaved configuration of the up-link and down-link chip sequences and dynamic ranging through the time-division-multiple-access protocol realize the interleaved transmission of bytes.