  In the manuscript, the simple but interesting results are reported on the
upper limits of NLRs sizes of a small sample of 38 low redshift ($z<0.1$) AGN
with double-peaked broad emission lines (double-peaked BLAGN), in order to
check whether the NLRs sizes in type-1 AGN and type-2 AGN obey the similar
empirical dependence on \o3~ luminosity. In order to correct the inclination
effects on projected NLRs sizes of type-1 AGN, the accretion disk origin is
commonly applied to describe the double-peaked broad H$\alpha$ leading to the
determined inclination angles of central disk-like BLRs of the 38 double-peaked
BLAGN. Then, considering the fixed SDSS fiber radius, the upper limits of NLRs
sizes of the 38 double-peaked BLAGN can be estimated. Meanwhile, the strong
linear correlation between continuum luminosity and \o3~ luminosity is applied
to confirm that the \o3~ emissions of the 38 double-peaked BLAGN are totally
covered in the SDSS fibers. Considering the reddening corrected measured \o3~
luminosity, the upper limits of NLRs sizes of the 38 double-peaked BLAGN are
within the 99.9999\% confidence interval of the expected results from the
empirical relation between NLRs sizes and \o3~ luminosity in the type-2 AGN. In
the current stage, there are no clues to challenge the Unified model of AGN,
through the space properties of NLRs.
