  Massive binary stars play a crucial role in many astrophysical fields.
Investigating the statistical properties of massive binary stars is essential
to trace the formation of massive stars and constrain the evolution of stellar
populations. However, no consensus has been achieved on the statistical
properties of massive binary stars, mainly due to the lack of a large and
homogeneous sample of spectroscopic observations. We study the intrinsic binary
fraction $f_{\rm b}^{\rm in}$ and distributions of mass ratio $f(q)$ and
orbital period $f(P)$ of early-type stars (comprised of O-, B-, and A-type
stars) and investigate their dependences on effective temperature $T_{\rm
eff}$, stellar metallicity [M/H], and the projection velocity $v\sin{i}$, based
on the homogeneous spectroscopic sample from the Large Sky Area Multi-Object
Fiber Spectroscopic Telescope (LAMOST) Data Release Eight (DR8). We found that
$f_{\rm b}^{\rm in}$ increases with increasing $T_\mathrm{eff}$. The binary
fraction is positively correlated with metallicity for spectra in the sample.
Over all the $v\sin{i}$ values we considered, the $f_{\rm b}^{\rm in}$ have
constant values of $\sim$50\%. It seems that the binary population is
relatively evenly distributed over a wide range of $v\sin{i}$ values, while the
whole sample shows that most of the stars are concentrated at low values of
$v\sin{i}$ (probably from strong wind and magnetic braking of single massive
stars) and at high values of $v\sin{i}$ (likely from the merging of binary
stars). Stellar evolution and binary interaction may be partly responsible for
this.There are no correlations found between $\pi$($\gamma$) and $T_{\rm eff}$,
nor for $\pi$($\gamma$) and [M/H]. The uncertainties of the distribution
decrease toward a larger sample size with higher observational cadence.
