The methods which only need one modulated pattern for fringe projection measurement mainly have Fourier transform profilometry, wavelet transform profilometry, and so on. The continuous complex Morlet wavelet based on exponent scale interval and reconstruction is used to retrieve the instantaneous phase of fringe pattern. For the continuous wavelet transform, the great enough noise can change the position of wavelet transform ridge, the probability that the ridge moves up with the influence of noise is greatest. So, the wavelet coefficients corresponding to the ridge and the closest larger scale are chosen, and the maximum between-class variance methord (OTSU) is used to prevent the interference caused by low frequency components; in order to overcome the speckle noise, the result of OTSU is modified and at last, the modified result is used to reconstruct the analytic carrier-frequency signal, and compute the intantaneous phase of the signal. The theoretical analysis and experimental results illustrate that the method is valid and robust.