The invention discloses a nano-silver deposited medical antibacterial polycarbonate material and a preparation method thereof. Firstly, amino groups on the surface of chitosan and bisphthalonitrile are subjected to a crosslinking reaction, an obtained amino-nitrile compound participates in an acrylonitrile polymerization reaction in the presence of an initiator, an antibacterial crosslinked polymer is obtained, antibacterial fiber is obtained through spinning and treated with hydrogen peroxide, hydroxylated antibacterial fiber is obtained, hydroxy of polytrimethylene carbonate is activated through glycol and is subjected with a condensation reaction with hydroxy on the surface of the antibacterial fiber, a silver nitrate water solution is added in the condensation reaction process, a reduction reaction is performed through polyvinylpyrrolidone, obtained nano-silver is deposited on the surface of the polymer through a condensation reaction, and the polycarbonate material is obtained.