The stability of a small unilamellar liposome, prepared by sonication from the turbid aqueous solutions of egg yolk phosphatidylcholine with the cuphorn ultrasonic system, were investigated by measuring the absorbance of visible light in the range of wavelengths from 425 nm to 750 nm. The absorbance of the freshly sonicated and centrifuged liposome solution followed the linear relationship with 1/wavelength⁴ of the Rayleigh scattering theory. For the incubated liposomal dispersions, a transient turbidity model was proposed in order to explain the change of turbidity by combining with Smoluchowski fast flocculation, and the model has been shown to be appropriate for the prediction of the changes of liposomal particles, i.e., number, size and shape.