  The lithium abundances for 378 G/K giants are derived with non-LTE correction
considered. Among these, there are 23 stars that host planetary systems. The
lithium abundance is investigated, as a function of metallicity, effective
temperature, and rotational velocity, as well as the impact of a giant planet
on G/K giants. The results show that the lithium abundance is a function of
metallicity and effective temperature. The lithium abundance has no correlation
with rotational velocity at vsini $<$ 10 km s$^{-1}$. Giants with planets
present lower lithium abundance and slow rotational velocity (vsini $<$ 4 km
s$^{-1}$). Our sample includes three Li-rich G/K giants, 36 Li-normal stars and
339 Li-depleted stars. The fraction of Li-rich stars in this sample agrees with
the general rate of less than 1$\%$ in literature, and the stars that show
normal amounts of Li are supposed to possess the same abundance at the current
interstellar medium. For the Li-depleted giants, Li deficiency may have already
taken place at the main sequence stage for many intermediate-mass (1.5-5
M$_{\odot}$) G/K giants. Finally, we present the lithium abundance and
kinematic parameters for an enlarged sample of 565 giants using a compilation
of literature, and confirm that the lithium abundance is a function of
metallicity and effective temperature. With the enlarged sample, we investigate
the differences between the lithium abundance in thin-/thick-disk giants, which
indicate that the lithium abundance in thick-disk giants is more depleted than
that in thin-disk giants.
