Method and system for improving accuracy of correction of fuel quantity at the time when recirculation valve is opened

A method for improving accuracy of correction of fuel quantity at the time when a recirculation valve (RCV) is opened, may include a step of correcting injection amount of fuel based on consideration factors when the RCV is operated to be opened. The consideration factors include property values of a flow path of the RCV, the flow path being mounted to an intake pipe to connect between a front end of a compressor close to the atmosphere and a rear end of the compressor adjacent to combustion chambers, a first calculation value obtained by calculating amount of air to be introduced into the combustion chambers after circulating from the flow path of the RCV to the intake pipe, and a second calculation value obtained by calculating amount of hydrocarbon to be introduced into the flow path of the RCV by purging evaporative gas.