Abstract: Under such working conditions that when the gas volume of downstream users can not he kepi at a sustained supply.at higger peak-valley differences, flow control valves may he installed at metering branch of gas offtake station to make flow control.It is pointed out that the control method has some problem in practicality.but the problem can he settled if the control valve is provided with replaceable ram and alloca-ted with relative rams based on the diameter of installed orifice flowmeter during gas supply to allow the flow control valve really to play a role of flow control.It is described in the paper that the technical reform to the flow control valve at gas offtake station is of significance in reducing metering loss.distributing gas flowrate.restraining turbulent flow and supporting stable gas supply.