In spectral extinction particle sizing technique, an inversion method in the dependent model is proposed, in which the commonly used bimodal, mix-bimodal, and monomodal particle size distributions are retrieved using the bimodal Johnson's S-B function as the assumed type of distribution function. The feasibility and reliability of this inversion method are investigated, and the inversion using the bimodal modified beta function as the assumed type of distribution function is also discussed for comparison. Numerical simulations and experimental results indicate that the commonly used particle size distributions can be retrieved well using the bimodal Johnson's S-B function as a versatile distribution function in the dependent model with the spectral extinction data. This inversion method not only overcomes the difficulty caused by the inability to determine the type of specified distribution function accurately beforehand, but also allows the description of different types of distributions by a single model. (C) 2009 Elsevier B.V. All rights reserved.