Abstract: Land type is an abstract concept. It is not an objective entity. Type exists only in certain concrete local forms. The scale size and complexity degree of the land individuals are varied. So different units of land should be distinguished. Only if the types are summarized within the local forms at the same level, a logical system of toxonomy can be taken. Therefore,the dividing of land individuals is the prerequisite of land classification. Meanwhile, this dividing also has following effects. To provide a framework for land data bank. To promise the statistical analysis to random samples of individuals in order to prove the correctness of land classification. To differentiate the details of the utilization to local forms that have been grouped into the sametype.Since the beginning of this century,geographers have been devoting themselves to the dividing hierarchy unit of physical geographical entities. This work is called Iand units hierarchy. The units of some authors and the definitions of the chief units are compared in this paper.Land units hierarchy is a scale concept, which relates to the size of area to a certain extent but means essentially the degree of complexity.The isomeric decreases and the homogeneous increases from the higher level units to the slower.The basic theory of land units hierarchy is the law on region differentiation, which depend mainly upon the geomqrphological differences,especially in middle and small areas. Therefore geomorphology is the chief factor of dividing land units hierarchy.The change of complexity degree between land units is continuous. So the hierarchy of land units can be divided iuto some continuous level. But it should be simple so that the result map can be recognized clearly. This demands a definition of a few basic level from the continuous series. These essential units and their characteristics are as follows.(1)Land element. It is a part of a land facet, and is the smallest units of land. All the physical geographical components within it are uniform. The exactly same measure of management can be taken in it for intensive kinds of land use. It should be called "Tu Di pian" (Iand piece) in Chinese.(2)Land facet. It is a group of linked land elements. Each land facet is homogeneous in form and fairly distincts from the surrounding land. Its lithology and deposit is also the same.One utilization should be exercised within its extent. It is called "Tu Di Mian" (land face) in Chinese.(3) Land system. It is a recurrant pattern of several kinds of land facet There is an associated pattern of simple land forms, vegetations, and soils over its range. One combination of land use (i.e. regional agricultural type) should be given to a land system. It is called "Tu Di Qun" (land crowd) in Chinese.