The utility model relates to a single-column and multi-sensor chromatogram device for online monitoring transformer oil. A plurality of sensors are combined to improve the detection sensitivity of ingredient gases by means of the property that gas selectivity of different types of sensors is different, and the problem of selecting semiconductor gas sensitive detectors of an online monitoring system of gases in the transformer oil is solved. The device comprises a carrier gas cylinder, a pressure reducing valve, a purifier, a pressure stabilizing valve, an oil-gas separation device, an sample injector, a chromatographic column separator, an incubator, a tee connecting head, a solenoid valve, a damper, semiconductor gas sensitive detectors and a spectrum waveform recorder, wherein the output of the sample injector is connected to the tee connecting head, at least one detecting channel is respectively connected on the two output ends of the tee connecting head in parallel, the solenoid valve, the damper and semiconductor gas sensitive detectors with different model numbers are sequentially connected in the detecting channel, and the outputs of the semiconductor gas sensitive detectors with different model numbers are respectively connected to the spectrum waveform recorder.