The invention provides a communication method of a multi-core 
plastic optical fiber system aiming at problems that an 
electric signal in transmission process is easy to be influenced by environment factors such as 
electromagnetic interference and the like, the transmission is unstable, and the degree of 
distortion is high. The communication method has the beneficial effect as follows: through the adoption of optical 
signal communication, the problems that the 
electric signal is seriously affected by 
electromagnetic interference in the transmission process and the degree of information 
distortion is high are solved; the optical 
signal transmission is stable and high-speed, the degree of 
distortion is low, and in particular, the complete truth of the 
signal transmission is guaranteed by adopting a plurality of 
modes; the optical signal is safe and reliable and hard to be tapped; the 
plastic optical fiber is large in core 
diameter, low in butt-joint 
optical coupling degree requirement, low in installation and disassembling cost, convenient and fast; the multi-core 
plastic optical fiber further reduces the 
optical fiber cost, and the communication rate is multiplied; and the multi-core plastic 
optical fiber solves the problem that the wiring in public places is disordered.