  We present measurements of the linear galaxy bias of H$\alpha$ and [OIII]
emission line galaxies (ELGs) for the High Latitude Spectroscopic Survey (HLSS)
of Nancy Grace Roman Space Telescope, using galaxy mocks constructed using
semi-analytical model for galaxy formation, {\it Galacticus}, with a large
cosmic volume and redshift coverage. We compute the two-point statistics of
galaxies in configuration space and measure linear bias within scales of
$10\sim50 h^{-1}$Mpc. We adopt different selection algorithms to investigate
the impact of the Roman line flux cut, as well as the effect of dust model used
to calibrate Galacticus, on the bias measurements. We consider galaxies with
H$\alpha$ and [OIII] emissions over the redshift range $1<z<3$, as specified by
the current baseline for the Roman HLSS. We find that the linear bias for the
H$\alpha$ and [OIII] ELGs can be expressed as a linear function with respect to
redshift: $b \simeq 0.88z+0.49$ for H$\alpha$ $(1<z<2)$, and $b \simeq
0.98z+0.49$ for [OIII] $(2<z<3)$. We have also measured the Halo Occupation
Distributions of these H$\alpha$ and [OIII] emission line galaxies to
understand their distribution within dark matter halos. Our results provide key
input to enable the reliable forecast of dark energy and cosmology constraints
from Roman.
