Harmony, unity and communication are the basic requirements for the progress of human culture and happiness. A harmony of human relations can be obtained, if “grammar of humanity” is known and be observed. “Grammar of humanity” is used in an analogical sense in this article, since the universe of human beings has been taken as a linguistic system. Human actions is a kind of language which includes all speechs and signs. Language can become a language, and be learned if and only if there is a grammar. The author contends that there is a grammar of humanity. The grammar can be known and observed. The article deals with the grammar of humanity by five sections.i)Indicating the language-learning-process. One learns language as well as the grammar.ii)On the foundations of the grammar of humanity.iii)The characteristics of the grammar and the conditions of formulization of the grammar.iv)The grammar and praxis.v)Meaning and perfection. The approaches are phenomenological and hermeneutical.