Abstract: This essay uses a great number of historical materials from China and other countries and numerous excavated human remains to prove irrefutably that after Japan invaded and occupied the Liaodong Peninsula 100 years ago，it carried out an inhuman policy of ordering widespread massacres.Altogether over 200，000 innocent people were slaughtered .To continue to argue that the Chinese people whom the Japanese imperialists ordered killed at that time were “soldiers in civilian clothing” is a lie.