In the hierarchical galaxy formation model , today ’ s galaxies are the product of frequent galaxy merging , triggering the activity of active galactic nuclei and forming a supermassive black hole binary .
A binary may become stalling at pc-scale and is expected to be detected in nearby normal galaxies , which is inconsistent with observations .
In this paper , we investigate the interaction of the supermassive binary black holes ( SMBBHs ) and an accretion disk and show that the stalling can be avoided due to the interaction and a rapid coalescence of SMMBHs can be reached .
A binary formed during galaxy merging within Hubble is most likely inclined with a random inclination angle and twists the accretion disk , aligning the inner part of the disk with the orbital plane on a time scale \sim 10 ^ { 3 } { yr } .
The twisted inner disk subsequently realigns the rotating central supermassive black hole on a time scale \la 10 ^ { 5 } { yr } 
due to the Bardeen-Peterson effect .
It is shown that the detected X-shaped structure in some FRII radio galaxies may be due to the interaction-realignment of binary and accretion disk occurred within the pc scale of the galaxy center .
The configuration is consistent very well with the observations of X-shaped radio sources .
X-shaped radio feature form only in FRII radio sources due to the strong interaction between the binary and a standard disk , while the absence of X-shaped FRI radio galaxies is due to that the interaction between the binary and the radiatively inefficient accretion flow in FRI radio sources is negligible .
The detection rate , \lambda _ { X } \sim 7 \% , of X-shaped structure in a sample of low luminous FRII radio galaxies implies that X-shaped feature forms in nearly all FRII radio sources of an average lifetime t _ { life } \sim 10 ^ { 8 } { yr } .
This is consistent with the estimates of net lifetime of QSO and radio galaxies and with the picture that the activity of active galactic nuclei is triggered by galaxy merging .
As the jet orients vertically to the accretion disk which is supposed to be aligned with galactic plane of host galaxy , the old wings in X-shaped radio sources are expected to be aligned with the minor axis of host galaxy while the orientation of the active jets distributes randomly .
It is suggested by the model that the binary would keep misaligned with the outer disk for most of the disk viscous time or the life time of FRII radio galaxies and the orientation of jet in most FRII radio galaxies distributes randomly .
As the binary-disk interaction in FRI radio galaxies is negligible or a source evolves from FRII- to FRI-type after the binary becomes aligned with the outer disk , the jets in most FRI radio galaxies is expected to be vertical to the accretion disk and thus the major axis of host galaxy .
We discuss the relationship of X-shaped and double-double radio galaxies ( DDRGs ) and suggest that all X-shaped radio sources would evolve into DDRGs after the coalescence of the SMBBHs and that most radio sources evolve from FRII- to FRI-type after an interruption of jet formation , implying that the average size of FRI radio sources is smaller than that of FRII radio galaxies .
The model is applied to two X-shaped radio sources 4C+01.30 and 3C293 and one DDRG source J0116-473 with a bar-like feature and show that the SMBBHs in the three objects are minor with mass ratio q \sim 0.1 - 0.3 .