The utility model discloses a multichannel ozone detecting instrument for a ring main unit. The multichannel ozone detecting instrument comprises a plurality of ozone sensors which are distributed inside the ring main units, pressure sensors which are arranged inside the ring main units, first A/D (analog/digital) converters corresponding to the ozone sensors one by one, second A/D converters corresponding to the pressure sensors one by one, a digital signal processor, a single chip microprocessor, an alarming device, a storage device, a keyboard and a display screen, wherein each ozone sensor is connected with the digital signal processor through the respective corresponding first A/D converter; each pressure sensor is connected with the digital signal processor through the respective corresponding second A/D converter; the digital signal processor, the alarming device, the storage device, the keyboard and the display screen are respectively connected with the single chip microprocessor. The ozone concentration inside the ring main unit and the air pressure inside each ring main unit are collected through multiple channels, so that the accurate measurement within a large range can be realized.