  We present two samples of $\hii$ galaxies from the Sloan Digital Sky Survey
(SDSS) spectroscopic observations data release 3. The electron
temperatures($T_e$) of 225 galaxies are calculated with the photoionized $\hii$
model and $T_e$ of 3997 galaxies are calculated with an empirical method. The
oxygen abundances from the $T_e$ methods of the two samples are determined
reliably. The oxygen abundances from a strong line metallicity indicator, such
as $R_{23}$, $P$, $N2$, and $O3N2$, are also calculated. We compared oxygen
abundances of $\hii$ galaxies obtained with the $T_e$ method, $R_{23}$ method,
$P$ method, $N2$ method, and $O3N2$method. The oxygen abundances derived with
the $T_e$ method are systematically lower by $\sim$0.2 dex than those derived
with the $R_{23}$ method, consistent with previous studies based on $\hii$
region samples. No clear offset for oxygen abundance was found between $T_e$
metallicity and $P$, $N2$ and $O3N2$ metallicity. When we studied the relation
between N/O and O/H, we found that in the metallicity regime of $\zoh > 7.95$,
the large scatter of the relation can be explained by the contribution of small
mass stars to the production of nitrogen. In the high metallicity regime, $\zoh
> 8.2$, nitrogen is primarily a secondary element produced by stars of all
masses.
