disclosed are a method for preparing biodegradable polymer materials , biodegradable polymer materials , and a product for fixing bone . the method includes a complex preparing step of preparing polylactide stereoisomeric complex by using a polymer having weight - average molecular weight more than 100 , 000 g / mol ; a molding step of compression - molding the complex ; a cooling step of cooling the compression - molded complex ; and an extruding step of solid state extruding the cooled complex . biodegradable polymer materials prepared by the method may be applied to a product for fixing bone or spine requiring high strength . biodegradable polymer materials may have no corrosion in the body , may require no additional operation for removal after healing bones and tissues , and may prevent stress shielding .