The invention relates to a high-strength chitosan-based anion-exchange membrane and a preparation method thereof. The anion-exchange membrane is prepared by the following steps: dissolving chitosan into a solvent, mechanically mixing with poly dimethyl diallyl ammonium chloride to obtain a homogeneous solution; performing an epoxy ring-opening reaction with epoxysilicone to obtain polymer sol; and preparing the high-strength chitosan-based anion-exchange membrane by using tetraethoxysilane as precursor through a sol-gel technology. According to the high-strength chitosan-based anion-exchange membrane, siloxane is used as a chemical cross-linking agent, the alcoxyl group Si-OCH3 in siloxane is hydrolyzed to generate an Si-OH structure, and a compact Si-O-Si three-dimensional reticular structure is formed by dehydration synthesis, so that the mechanical strength of the membrane is furthest improved, the swelling degree of a CS/PDDA compound anion-exchange membrane can be reduced, the mechanical performance and size stability of the membrane are improved, and the service life of the membrane can be prolonged.