A method for instantaneous three-dimensional profile measurement of a continually vibrating cantilever beam is proposed. The moiré fringes containing the three-dimensional patterns information of a continually vibrating cantilever beam, generated by the interference of the grating lines and their shadows, are captured by a high\|speed CCD camera. Two light sources are used to enhance the illumination of the fringe patterns. Fourier transform method is adopted to analyze the time-sequence fringe patterns, and the outer extended interpolation is used to decline the phase error resulting from the leakage of the frequency. The phase unwrapping method is used to unwrap the phase in the dynamic process, the instantaneous three-dimensional profile is obtained and the continually vibrating process of the cantilever beam is reconstructed.