The present invention provides a digital optical fiber-based distributed signal control system. The system mainly comprises a wireless signal access control module, a detection module, and a private network module. By means of reasonable frequency allocation and pre-selection filtering processing, modules can work together to implement control and detection of unauthorized mobile phone signals and guarantee communications of legal mobile phones, thereby achieving efficient coverage of a signal control area. A main control signal generated by a main control signal unit (SU) and an auxiliary control signal generated by a remote unit (RU) are mixed according to an algorithm, to achieve a better control effect in the entire signal control area.