  We analyze the physical properties of post-starburst AGN SDSS
J085338.27+033246.1 according to its optical spectrum and discuss its
implications on AGN's evolution. The spectra PCA method is developed to extract
emission lines and absorption features from the total light spectrum. The
emission-line analysis indicates that the object can be classified as a NLS1
with FeII/H$\beta_{\rm{B}}=2.4\pm0.2$, large Eddington ratio ($\sim0.34$),
small black hole mass ($\sim1.1\times10^{7}M_{\odot}$) and intermediately
strong radio emission. A simple SSP model indicates that the absorption
features are reproduced by a $\sim$100 Myr old starburst with a mass of
$\sim7\times10^{9}M_{\odot}$ rather well. The current SFR
$\sim3.0M_{\odot}\rm{yr^{-1}}$ inferred from the [OII] emission is much smaller
than the past average SFR$\sim70M_{\odot}\rm{yr^{-1}}$, however. The line ratio
diagnosis using the BPT diagrams indicates that the narrow emission lines are
almost entirely emitted from HII regions. We further discuss a possible
evolutionary path that links AGN and starburst phenomena.
