A method for preparing an anti-bacterial and anti-ultraviolet multifunctional chemical fiber includes: dissolving several soluble metal salts and a polymer complexing dispersant into water to prepare an aqueous solution; adding into a polymer monomer; reacting under microwave or hydrothermal action to obtain a polymer monomer containing multifunctional nano oxides; adding the polymer monomer with other monomer, catalyst, initiator, stabilizer, and the like into a polymerization reactor; and carrying out esterification, polycondensation or copolymerization to obtain a polymer melt, and carrying out spinning or ribbon casting and granule cutting to obtain an anti-bacterial and anti-ultraviolet multifunctional chemical fiber or masterbatch chips. By generating nano metal oxides in the monomer in situ before the polymerization reaction, small particle sizes and dispersibility of the nano metal oxide are ensured; the chemical fiber has efficient, durable antibacterial and anti-ultraviolet functions and is free of metal ion precipitation.