Optical-fiber vortex flowmeters are particularly applied in the measurement of fluid flows where instruments with no moving parts and wide range ability are required, especially under the flammable explosive environment. But because there is the impurity unavoidably, including the air bubble, the solid particle and so on, which makes the signal includes the massive noises and other indefinite ingredient, thus affects the authenticity of the data. It is widely acknowledged that process conditions influence the operation of a vortex flowmeter and that fluctuations in the flow affect the complex phenomenon of vortex street formation. In this paper, a digital signal processing algorithm based on wavelet method is presented. In the algorithm, a powerful mathematical tool-wavelet transform method is used to check out the frequency of the signal of the vortex flowmeter which has been submerged under the noises, and simulation results prove its feasibility.