Abstract:
　 The narrow line region(NLR) is the biggest structure of radio-quiet Seyfert galaxies. A commonly used tracer of NLR is the [OIII]5007 line, which is the strongest narrow line in optical band. The [OIII] strength, quantified as Equivalent Width(EW), of Seyfert1 galaxies spans a large range and this phenomenon is not well understood. We find that the EW([OIII]) is not linked to fundamental AGN parameters like Black hole mass, luminosity and Eddington ratio, but closely linked to the [OIII] outflow velocity. This trend is possible driven by the ISM gas in host galaxies or(and) by inclination effect. Besides, the inner part of [OIII] emitting region is obscured by the torus and it is closely linked to the warm dust in AGN. The strong correlation between the inner NLR and the obscuring material could shed light on the NLR physics and constrain the torus models.