Abstract Whether the public affairs are executed by central or local government in Taiwan is based on the constitution, law and orders. The clauses of constitution were derived from the ¡§Principle of proper separation of competence¡¨, asserted first by Dr. Sun Yet-sen. From these clauses local and central governments in Taiwan should deal with different things which are properly divided according to their nature. But those clauses were not executed because of the unpredicted failure in mainland. For the reasons to initiate and regulate the local-self government institution, many acts and decrees had enacted after 1949, which gradually twisted the meaning of previous clauses that are ought to be obeyed. Besides, the increasing chaos happened recently about the struggle of expenditure in local and central authorities, showed the problems as the result of deviation. This thesis elaborates on the articles of institution which combines the clauses in the constitution and the ultimate aim of local self-government, includes democracy, separation of power in vertical level, and how the local governments are protected by law. This thesis also describes and analyses the whole juristic construction in separating local and central affairs, and, with a new-institutionalist approach, tries to find the key factors which make this institution evolved, changed and disobeyed the principles which they should be fulfilled. With these factors, this thesis finds that the deviation of the institution which is ought to be fulfilled is evolved by the ¡§path¡¨, the way it changed the previous aim or purpose. Consequently, once the ¡§path¡¨ had formatted, the actors of institution-local governments and central governments, will not obey the constitutional clauses and will keep exercising the deviated system of institution about the separation of central and local affairs.