The invention belongs to the technical field of petroleum development and relates to a fracturing site CO2 flow monitoring device and a use method thereof. The device comprises a hoisting shell, an operation display screen, a wireless data receiving module, a main control module, a storage battery, a wireless data transmission module, and a plurality of mass flowmeters; the operation display screen and the wireless data receiving module are fixed on the outside of the shell; the main control module, the storage battery and the wireless data transmission module are fixed inside the shell; and the plurality of mass flowmetersa are fixed in the shell. The fracturing site CO2 flow monitoring device of the invention is safe, reliable and easy to move and can be applied to the Fracturing transformation of the field of gasoline technologies. The fracturing site CO2 flow monitoring device is used for the real-time monitoring of CO2 instantaneous flow, total flow, pressure, temperature and other fracturing data of a CO2 fracturing site. The fracturing site CO2 flow monitoring device is low in error and high in accuracy. With the fracturing site CO2 flow monitoring device adopted, the defect of failure to monitor temperature, pressure and other parameters in conventional hydraulic fracturing equipment and the defect of large flow metering errors can be eliminated.