A control method of an exhaust gas purification system, in an internal combustion engine mounted on a vehicle provided with a continuous regeneration diesel particulate filter in the exhaust gas passage thereof; comprising the steps of: performing normal operation unrelated to regeneration of the continuous regeneration- diesel particulate filter; detecting the collecting quantity (ΔPm) of collected matters in the continuous regeneration diesel particulate filter, detecting the travel distance (ΔMc) covered by the vehicle after diesel particulate filter regeneration; performing a forced regeneration control in which a multi-injection in a fuel injection into the cylinder of the engine is performed for raising the exhaust gas temperature to the active temperature of an oxidation catalyst, and thereafter a post injection is performed for raising a filter inlet exhaust gas temperature, thereby the collected matters are forcibly burned and the continuous regeneration diesel particulate filter is regenerated; characterised in that in case the collecting quantity (ΔPm) detected by the collecting quantity detection means exceeds a predetermined first temperature rising judgment collecting quantity (ΔP01) lower than a predetermined judgment collecting quantity (ΔP1), an exhaust gas temperature raising control by multi-injection in the control of fuel injection into cylinder is performed, which is thereafter stopped when the collecting quantity (ΔPm) detected by the collecting quantity detection means becomes lower than a predetermined second temperature rising judgment collecting quantity (ΔP02) lower than the predetermined first temperature rising judgment collecting quantity (ΔP01), and in case the collecting quantity (ΔPm) detected by said collecting quantity detection means is higher than a predetermined judgment collecting quantity (ΔP1), a warning means for urging a warning for prompting a driver to actuate the forced regeneration control means is activated, if the covered travel distance (ΔMc) after the start of the accumulation reached a predetermined judgment travel distance (ΔM1), which indicates the lower limit value at which oil dilution problems do not occur upon manual regeneration. performing normal operation unrelated to regeneration of the continuous regeneration- diesel particulate filter; detecting the collecting quantity (ΔPm) of collected matters in the continuous regeneration diesel particulate filter, detecting the travel distance (ΔMc) covered by the vehicle after diesel particulate filter regeneration; performing a forced regeneration control in which a multi-injection in a fuel injection into the cylinder of the engine is performed for raising the exhaust gas temperature to the active temperature of an oxidation catalyst, and thereafter a post injection is performed for raising a filter inlet exhaust gas temperature, thereby the collected matters are forcibly burned and the continuous regeneration diesel particulate filter is regenerated; characterised in that in case the collecting quantity (ΔPm) detected by the collecting quantity detection means exceeds a predetermined first temperature rising judgment collecting quantity (ΔP01) lower than a predetermined judgment collecting quantity (ΔP1), an exhaust gas temperature raising control by multi-injection in the control of fuel injection into cylinder is performed, which is thereafter stopped when the collecting quantity (ΔPm) detected by the collecting quantity detection means becomes lower than a predetermined second temperature rising judgment collecting quantity (ΔP02) lower than the predetermined first temperature rising judgment collecting quantity (ΔP01), and in case the collecting quantity (ΔPm) detected by said collecting quantity detection means is higher than a predetermined judgment collecting quantity (ΔP1), a warning means for urging a warning for prompting a driver to actuate the forced regeneration control means is activated, if the covered travel distance (ΔMc) after the start of the accumulation reached a predetermined judgment travel distance (ΔM1), which indicates the lower limit value at which oil dilution problems do not occur upon manual regeneration.