Data Release 4 (DR4, Adelman-McCarthy et al. 2004) main galaxy sample (Strauss et al. 2002), and presented their basic photometric properties including correlations of disk scalelength versus B-band absolute magnitude and distance, stellar populations from colors. In Liang et al. (2010), we studied the spectroscopic properties of this large sample of LSBGs, including dust extinction, strong emission-line ratios, metallicities and stellar mass-metallicity relations. In this work, we firstly extend the sample from DR4 to DR7, then try to obtain their multiwavelength data from FUV to Ks based on the public survey data from GALEX GR4/GR5 and 2MASS Extended Source Catalogue (XSC). Then, we use the evolutionary population synthesis (EPS) model PEGASE to fit their multiwavelength SEDs from FUV to NIR, and derive the ages of these galaxies. At the same time, a large sample of nearly face-on disk high surface brightness galaxies (HSBGs, 5,886) with $\mu_{0}$(B) $<$ 22 mag arcsec$^{-2}$ are selected and applied to same analyses for comparisons.

This paper is organized as follows. In Sect.2, we describe the multiwavelength observations and the selected sample. In Sect.3 we describe the EPS model PEGASE, which is what we used to fit the SEDs of the galaxies, and the adopted parameters. 