Abstract: The reason that the constitution of different countries has different expressions of the states structure mainly attributes to the differences of constitutional development history,legal culture,ideology and other factors.The constitution of a federal country always describes the states structure by naming it a federal country directly or listing the federal members in the preface or foreword.While the constitution of unitary state does not name it a unitary state directly,nor expresses the states structure by using the dear word of unitary system in the full context of the constitution. However,no matter the constitution of a federal state or that of a unitary state,the content of the expression of the states structure is the division of power between the central and local governments.