So-called sound-shift in the present dissertation is a change of speech sound in the process of developing and using, involving cognate word, dialect word, lian-mian word, tong jia zi and name of people, name of area, name of race and so on . A great number of facts of language show:sound-shift is an extraordinary complicated phenomenon related to a lot of reseach area in phonology xun gu xue , historical dialectology, historical lexicology, character and etc. As far as type of sound-shift is concerned, it includes not only sound-shift of cognate which once to be interested mostly, but also sound-shift of dialect, sound-shift of jia-jie, sound-shift of lian-mian, sound-shift of wrong-sound and soon.. In other word, all most changes of relation between sound and meaning are sound-shift. The studying of sound-shift in the past is mainly limited to sound-shift of cognate or subordinate to the studying of cognate and summary or systematic studying in pattern, law and mechanism is lacked. My dissertation will study sound-shift overall and systematically. It will provide a basic from of theory for inducing the system of sound and meaning of Chinese. Main contentFirst: Introduction. Second: Terminology of sound-shift. Third: Regulation of sound. Forth: principle of sound-shirt. Fifth: law of sound-shirt, sixth: Restriction of sound-shift. Seventh: conclusion. Main point of view1. Now that sound-shift is an objective phenomenon. It does not change on people' s will, therefore, we should have a scientific knowledge for it. On the contrary. We need not worry about talking about it and shouldn' t arbitrarity take the method for character game or myth, which is applied to explan the meaning by principle of sound-shift.2. Sound-shift has a regularity which is in the ancients' works of xun gu xue, we will sum up the law by the pricinple of modern linguist is and improve it on theory. These research will privode helpful introdution for xun gu of literature.3. Sound-shirt has a restricted mechanism which is mainly come from the rest ion of language and of relation between sound and meaning. The two respects are dermined that it is impossible for sound-shift to be explan anywhere. It is a unilateral to take sound-shift for character game or myth, and the scientific spirit of linguistics is violated if the basic law of sound-shift is neglected with the ralation between being explaned wantonly.Main method of research1. To combine synchronic research with diachronic research.2. To combine individual research with systematic research.3. To combine sound-shift with comparison in other discipline.