Spherical dust aerosol model is demonstrated not sufficient for retrieving dust aerosol properties from multi-spectral multi-angular polarimetry measurements. Non-sphericity effect of dust aerosol is shown to be pronounced for the polarization as well as radiance observations. We take advantage of wide spectral range and high resolution of MODIS to detect dusty pixel and make use of multi-directional polarization capability of POLDER to retrieve aspect ratio of dust aerosols. It is found that dust aerosol is far from spherical shape. Best-fit aspect ratio is also obtained for optically thick dusty pixels.