The utility model relates to the technical field of power supply and transformation, in particular to a three-way device for gas chromatographic analysis of insulating oil. The three-way device for the gas chromatographic analysis of the insulating oil is arranged between a pressure reducing valve and a purifier. The three-way device has the benefits that the three-way device is arranged between the pressure reducing valve and the purifier, and a sealing rubber mat is mounted inside the three-way device; the insulating oil can be taken out by an injector and is vibrated and degassed, and 5mL of nitrogen is used for next test, so that waste of the nitrogen is avoided, the cost is reduced, a carrier gas cylinder serves as a carrier gas entering gas path control system, and the device is used for vibrating and degassing the insulating oil; two original nitrogen bottles are replaced by one nitrogen bottle, and the occupation space is saved. The three-way device for the gas chromatographic analysis of the insulating oil is simple in structure, easy and practical, and the requirements on the chromatographic analysis of the insulating oil are met.