In this paper,we study the matched queueing system,MoPH/G/1,where the type-Ⅰ input is a Poisson process,the type-Ⅱ input is a PH renewal process, and the service times are i.i.d. random variables. A necessary and sufficient condition for the stationariness of the system is given.The expectations of the length of the non-idle period and the number of customers served in a non-idle period are obtained.