  Spectroscopic observations of a sample of 73 very luminous IRAS galaxies
(log(LIR/Lsun)>=11.5 for H0=50km s^{-1} Mpc^{-1},q0=0.5) from the 2Jy red-
shift survey catalogue were carried out using the 2.16m telescope at the
Beijing Astronomical Observatory. The observational data, including the optical
images (extracted from Digital Sky Survey) and spectra for these galaxies, are
presented in paper I (Wu et al., 1998). In this paper, we give the spectral and
morphological classifications for these very luminous IRAS galaxies (VLIRGs).
We show that about 60% of VLIRGs exhibit AGN-like spectra (Seyfert 1s, Seyfert
2s, LINER-like galaxies). This fraction goes up to 82% for the ultraluminous
IRAS galaxies (ULIRGs) subsample (Log(LIR/ Lsun) >= 12.0). 56% of the VLIRGs
show strong interaction or merging signa- tures; this fraction rises to 91% for
the ULIRGs. These statistical results strongly suggest that interaction
triggers nuclear activities and enhances the infrared luminosity. We find that
LINER and a mixture type which have optical properties of both HII galaxies and
LINERs could be at the transi- tion stage from infrared luminous HII galaxies
to AGNs; their main energy production is from starbursts as well as AGNs. Both
infrared luminosities and Ha equivalent widths increase dramatically as nuclear
separations between VLIRGs and their nearest neighbors decrease. There is
little doubt that strong starbursts happen in the nuclei of VLIRGs. Assuming
class 0 as advanced merger, we construct a simple merger sequence, from
morphological classes 1 to 4 (with near or far companions), to class 5 and 6
(interacting pairs and mergers) and then to class 0 (isolated galax- ies).
Along this sequence, VLIRGs evolve from HII galaxies to AGNs.
