We present two samples of \hii galaxies from the Sloan Digital Sky Survey
(SDSS) spectroscopic observations data release 3. The electron
temperatures(Te) of 225 galaxies are calculated with the photoionized \hii
model and Te of 3997 galaxies are calculated with an empirical method. The
oxygen abundances from the Te methods of the two samples are determined
reliably. The oxygen abundances from a strong line metallicity indicator, such
as R23, P, N2, and O3N2, are also calculated. We compared oxygen
abundances of \hii galaxies obtained with the Te method, R23 method,
P method, N2 method, and O3N2method. The oxygen abundances derived with
the Te method are systematically lower by ∼0.2 dex than those derived
with the R23 method, consistent with previous studies based on \hii
region samples. No clear offset for oxygen abundance was found between Te
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.Comment: 7 pages, 3 figures. A&A accepte