Due to the poor wireless transmission in the long tunnels, conventional communication technique cannot meet the high-quality communication demands of the passengers. A ROF (Radio over Fiber) distributed tunnel communication system employing WDM-PON (Wavelength Division Multiplex-Passive Optical Network) was proposed. By combining the WDM and DAS (Distributed Antenna System) techniques, a wireless access network can be achieved to provide different wireless services through optical channels. Moreover, the transmission bandwidth can be increased by using this proposed scheme which can also suppress the signal degradation under the scenario of tunnel transmission. A full-duplex ROF platform was experimentally demonstrated. The optical generation and transmission of electrical 16/64QAM vector signals at 24 GHz were achieved. And the feasibility of the scheme was verified by measuring the EVM value of the uplink and downlink.