  The quantum anomalous Hall state with a large band gap and a high Chern
number is significant for practical applications in spintronics. By performing
first-principles calculations, we investigate electronic properties of the
fully fluorinated 1T-MoSe$_{2}$ monolayer. Without considering the spin-orbit
coupling, the band structure demonstrates single-spin semi-metallic properties
and the trigonal warping around $K_{\pm}$ valleys. The introduction of the
spin-orbit coupling opens considerable band gaps of $117.2$ meV around the two
valleys, leading to a nontrivial quantum anomalous Hall state with a Chern
number of $|C|=2$, which provides two chiral dissipationless transport channels
from topological edge states and associated quantized anomalous Hall
conductivity. In addition, an effective model is constructed to describe the
low-energy physics of the monolayer. Our findings in the MoSe$_{2}$F$_{2}$
monolayer sheds light on large-gap quantum anomalous Hall states in
two-dimensional materials with the chemical functionalization, and provides
opportunities in designing low-power and noise-tolerant spintronic devices.
