Coherent optical orthogonal frequency division multiplexing (CO-OFDM) transmission has attracted special attention in numerous studies due to its interesting and efficient transmission performance. Wavelength-division multiplexing (WDM) technology improves system capacity by increasing the number of parallel transmission wavelength in optical fiber. The combination of coherent optical orthogonal frequency division multiplexing (OFDM) and WDM technology in optical fiber communication can build high speed rate, large capacity and low cost for optical transmission networks. Applications of theoretical model and the basic principles of WDM system using coherent optical OFDM were introduced. A simulation experiment of 100 Gb/s×32-channel WDM transmission system was derived from the coherent optical OFDM and the transmission performance of the system were studied. The simulation shows that system Q of the WDM channels at 3.2 Tb/s is potentially over 16.0 dB for a transmission up to 1500 km-long standard single mode fiber without any optical dispersion and nonlinear compensation.