Dietrich et al. 2012, Eracleous et al. 1997, Livio & Xu 1997, Oke 1987, Perez et al. 1988, Popovic et al. 2011, Shapovalova et al. 2001, 2010, Zhang 2011a). Then based on the proposed theoretical accretion disk model, besides the different line profiles, we try to find some interesting distinctions between the double-peaked emitter 3C390.3 and normal broad line AGN, which is the main objective of our manuscript.

As we commonly know that motions of broad emission line clouds in BLR (broad emission line regions) of AGN are gravitationally dominated by central mass of AGN (Gaskell 1988, 1996, Krause et al. 2011, Kollatschny & Zetzl1 2011, Netzer & Marziani 2010, Peterson & Wandel 1999, Wandel et al. 1999, and references therein), which provides strong evidence for applying Virialization assumption to estimate virial black hole masses of broad line AGN ( Bennert et al. 2011, Collin et al. 2006, Greene & Ho 2004, 2005, Kelly & Bechtold 2007, Marziani et al. 2003, Netzer & Marziani 2010, Onken et al. 2004, Park et al. 2012, Peterson et al. 2004, Peterson 2010, Rafiee & Hall 2011, Shen & Liu 2012, Sulentic et al., 2000, Vestergaard 2002, Wu et al. 2004). Then based on 