A use of platinum nanoparticles for manufacturing anti-cancer drugs being selectable anti-cancer drugs only under photobiotic environment is disclosed. A method of manufacturing the platinum nanoparticles is further disclosed. The method of manufacturing the platinum nanoparticles comprises: mixing dihydrogen hexachloroplatinate (IV) hexahydrate with a protector to obtain a mixture, while the mixture followed react with sodium hydroxide under 100~140℃ for 15~60 minutes to generate the platinum nanoparticles.本發明係一種鉑奈米粒子用於製備治療癌症之藥物的用途,係提供一種光能環境下始具有選擇性毒殺癌細胞之藥物。本發明另提供該鉑奈米粒子之製作方法,係包含混合一氯鉑酸六水合物與一保護劑,得一混合液,使該混合液於100~140℃下,與一氫氧化鈉反應15~60分鐘,以生成該鉑奈米粒子。