Power line communication(PLC) is a kind of communication technology, was made use of controling a frequency narrow band, but as the PLC technology developing, in the near future get to the commercial step that is broadband PLC upto 30 MHz. This paper deals with the PLC of electric railway using capacitive signal coupler. An AC arrester for catenary is used as a capacitive signal coupler, has the characteristic of capacitor. As a result of field test, a messenger wire used PLC contain much of conducted noise about overall frequency band and also signal attenuation rate increased with increasing frequency between two points. and the communication speed of PLC used messenger wire is 793kbps at a distance of 40m. Experimental results show the possibility of PLC using a messenger wire and an AC arrester for catenary at electric railway.