A high-precision vortex flow meter includes a blunt body having a predetermined dimension and being arranged inside a fluid channel to serve as a vortex shedder. The vortex flow meter also includes a temperature detecting device for detecting the vortex shedder temperature and a temperature control element for adjusting the vortex shedder temperature. A frequency measuring device is arranged in the downstream section of the blunt body for detecting the vortex shedding frequency. From the measured temperatures of the upstream fluid flow and that of the blunt body, an effective temperature and a temperature ratio are calculated. The kinematic viscosity of the fluid is looked up from database. By using the relationship between the Strouhal number and Reynolds number, the fluid flow rate is calculated. By employing different blunt body temperature, the measurement range of the flow meter can be broadly extended.