The invention relates to a vortex shedding flow meter based on self-adaptive fast Fourier transformation, which comprises a charge amplifier, a first filter, a program-controlled voltage amplifier, a second filter, a program-controlled scmitt trigger, a bias voltage circuit, a singlechip computer, an LDO (Low Dropout Regulator) circuit, a reset circuit, a key input, a 4-20mA output circuit and anLCD (Liquid Crystal Display) circuit. A signal generated by a vortex shedding sensor is connected with the charge amplifier; the output of the charge amplifier is connected with the first filter; theoutput of the first filter is connected with the program-controlled voltage amplifier; the output of the program-controlled voltage amplifier is connected with the second filter; the output of the second filter is divided into two paths, wherein one path is connected with the singlechip computer; the other path is connected with the program-controlled scmitt trigger; and the program-controlled scmitt trigger is connected with the singlechip computer. According to the vortex shedding flow meter disclosed by the invention, various noises can be effectively inhibited and low-flow and high-precision measurement is realized, thereby the measuring range ratio is enlarged and the measuring precision and the sensitivity are improved.