LSBGs (O’Neil et al. 1997) and the most common cases of “blue LSBGs" as late-type, disk-dominated spirals with $\mu_{0}$(B)$>$ 22 mag arcsec$^{-2}$ (Zhong et al. 2008 and the references therein). The LSBGs were generally thought to be unevolved systems with low metallicity (McGaugh 1994), low star formation rate (van der Hulst et al. 1993), a relatively high gas fraction (de Blok et al. 1996) and large amounts of dark matter (de Blok & McGaugh 1997). The age of LSBG is also an important topic to study.

The ages of the LSBGs have long been a matter of controversy. Broadband photometric studies, complemented by H$\alpha$ emission line data and synthetic stellar population modeling, predict quite a wide range for the ages of blue LSBGs: from 1-2 Gyr (Zackrisson et al. 2005) to 7-9 Gyr (Padoan et al., 1997; Jimenez et al. 1998). Ronnback & Bergvall (1994) carried out the multicolor studies of a sample of extremely blue galaxies with only small radial color gradients. In their work, BVI photometry was interpreted using spectral evolutionary models, and ages typically higher than 3 Gyr were found. Using optical/near-infrared (NIR) broadband photometry together with H$\alpha$ emission line data for a subsample of this sample, 