Deducing epithelial dysplasia from Light Scattering Spectroscopy (LSS) is an inverse problem,which can be transformed into inverting the size change of cellular nucleus.Based on the simulated single scattering polarized spectroscopy,Projection algorithm was employed to extract the size distribution of cellular nucleus.Projection algorithm regards the solution of equations as a point of the multi-dimension space,so the real value can be approached by finding out a series of project points on each hyperplane.Simulation results show that Projection algorithm has excellent inversion precision in both single-peaked and bimodal distribution,which implies its potential to increase the sensitivity of detection of epithelial dysplasia with light scattering spectroscopy.