The invention relates to a residual carbon analysis system of an infrared CO2 detector, which is formed by sequentially connecting an air source, a constant pressure valve, a manometer and a four-way valve, wherein the four-way valve is connected with an electromagnetic valve AF and an electromagnetic valve BF which are connected with an air cylinder; the inlet end of a mass flowmeter is connected with the four-way valve, and the outlet end of the mass flowmeter is connected with a simulation four-way valve which is connected with an injection rod on the air cylinder and an infrared CO2 detection unit so that CO2 is expelled by the simulation four-way valve; and an oxidation furnace is connected with the infrared CO2 detection unit which is connected with a computer host. The invention has the advantages of convenient maintenance, high sensitivity, low noise and extreme high detection speed, only needs one air source path, adds the blowback function, avoids the errors of analysis results due to the pollution of a furnace body, improves the service life and the anti-fatigue degree of the system, can continuously carry out analysis, and can shorten the analysis period.