Otitis media with effusion (OME) is a common middle ear inflammation for preschool-age children, with the presence of fluid in the middle ear cavity (MEC). Although the biomechanical abnormalities induced by OME has been evaluated by many studies through measuring the vibration pattern of the tympanic membrane (TM), the precise and quantitative assessment of severity at different stages of OME is still not fully achieved, and the diagnosis still largely depends on the subjective rating of physicians. To provide reliable and objective evidence for the diagnosis, we developed a new algorithm to process the full-field TM surface motion data acquired by scanning laser Doppler vibrometer (SLDV). The frequency bands and areas on the TM highly sensitive to the effusion amount and viscosity in the MEC were identified.