Abstract: The consensus definition from Sunnite viewpoint is “the consentaneous of Prophet Mohammad nation’s clergymen on a juridical order” and from Shiah viewpoint is �the consentaneous of some Muslims that they reveal the Imam’s words. The consensus difference from Sunnite and Shiah viewpoint is that argument criterion and consensus validity besides Shiah is detection from Imam but from Sunnite viewpoint, consensus validity is through Islamic nation consentaneous. The most important ways of Imam’s words detection from consensus are sensational method (initiatory consensus) favoural method and sensational method. The consensus divisions are as the acquired and narrated consensus a consensus that clergyman studies and researches on the Ulema’s opinions personally and it is called acquired consensus and that quoted acquired consensus by others is called narrated consensus. The compound consensus whenever there were only two opinions between the Ulema in a theorem it is concluded that they would negate third opinion with together and it is called compound consensus technically. The difference between consensus and narration is that news and narrations show Sunnah and we can impute to textual principles about them such as verbal principles and literal principles but consensus is a non-textual reason and it should content with appointed quantity. After survey the book and Sunnah we would study on the third reason namely consensus. In this direction, first consensus definition is considered then consensus historic background is mentioned. After that consensus argument is studied and finally consensus kinds are surveyed.