The present invention provides a C-RAN based wireless access system including a centralized baseband processing cell, a transmission network, a radio remote unit (RRU), and a digital front end wherein the centralized baseband processing cell communicates with the digital front end via the transmission network. The digital front end also communicates with the RRU. The system utilizes the digital front end to process CPRI data and realizes partial physical layer processing function in the digital front end so that the processed CPRI data only needs to be interacted with the base band cell and only effective data on frequency domains are transmitted to the centralized base band processing cell, which reduces the transmission of redundant data, and greatly lowers the requirement of data transmission for the switching network bandwidth. This also means that the requirement for CPRI side bandwidth is lowered to be compatible with the access of more RRUs. The system of the invention reduces the bandwidth requirement in a data transmission process, realizes the real-time knowing of the system's working condition and real-time dynamic configuration, and realizes the maximization of the bandwidth utilization rate and the resource scheduling optimization.