The invention discloses a balloon-borne vertical detection system for atmospheric boundary layer NO2, and belongs to the field of atmospheric pollution monitoring. The system comprises a high altitude data collection and adjustment module, a high altitude data transmission module, a sounding balloon device, a land data transmission module and a land data analysis module, wherein the high altitude data collection and adjustment module comprises a NO2 electrochemical sensor, a reference electrochemical sensor, a low temperature drift signal amplification and filtering circuit, a temperature and humidity sensor, a GPS module, a DSP main control board and a power module; the high altitude data transmission module comprises a wireless serial port unvarnished transmission module; the sounding balloon device comprises a meteorological sounding balloon; the land data transmission module comprises a wireless serial port unvarnished transmission module and a USB to serial port module; the land data analysis module comprises a LabVIE2015 platform and an Origin8 platform. Compared with the traditional NO2 detection equipment, the device has the advantages that the device highlights small size and portability, can realize high precision vertical measurement on the atmospheric boundary layer NO2, can guarantee the stability and reliability of detection results in high altitude complex environment, and has a wide development prospect.