The Lee Yi-yuan Case or the Campbell Assault Case in 1924 is a special Sino-foreign conflict with historical significance. For uncertain reasons, the former guard of Ministry of Army, Lee Yi-yuan beating an Italian, an American and a Briton near the Peking Embassy District on April 13, 1924, caused a grave international dispute. What is the truth about the case? Baptized by the Chinese nationalism, how was this Chinese soldier, viewed by foreigners as a crazy desperado, turned into a national hero, a symbol to brave foreigners' authority and shield China's sovereignty by the public opinion? The process of negotiation is pregnant with meanings, involving with the unequal relationship between Chinese people and foreigners, consular jurisdiction and the propaganda behind the international politics.