Control method for an exhaust gas purification system and an exhaust gas purification system

The present invention concerns a exhaust gas purification system (1), provided with a continuous regeneration-type DPF device (13) having a filter (13b) for collecting PM in exhaust gas (G), provided in an exhaust gas passage (12) of an internal combustion engine (10) provided with an EGR system, for supplying unburned fuel to exhaust gas (G) flowing in the continuous regeneration-type DPF device (13) during the forced regeneration control for regenerating the filter (13b) by forcibly burning PM collected by the filter (13b),characterized by stopping the recirculation of EGR gas (Ge) to the intake passage (14) side in the EGR system, when unburned fuel is supplied to exhaust gas (G) during the forced regeneration control.This prevents the blocking of EGR passage (15) and the sticking of intake valve and so on, caused by the unburned fuel supplied into exhaust gas (G), during the forced regeneration control of the continuous regeneration-type DPF device (13). And this prevents engine troubles caused by these problems.