With more and more dealing of foreign affairs with western countries especially under the pressure of force, Late Qing government had to gradually touch and learn western laws. Missionaries in China had introduced western legislative concepts before the Opium War, and after that they mainly translated works of international laws, which helped to shape new diplomatic ideas in that era. From the Sino-Japan War to the end of Qing Dynasty, emphasis was laid on the introduction of various Department Laws and constitutional laws. The introduction and translation of western legal theories, laws and systems had great influence on the decline of Chinese conventional laws and the legal reformation. It was doomed with historical limitations but objectively promoted the modern legal process.