According to the theory of soil and water conservation and managing practices, the minimum basic management unit is defined as conservation patch in this paper, which refers to the patch of soil and water conservation. This paper introduces the status of the basic management unit of soil and water conservation in China, aimed to elucidate the definition, implications, characteristics, division method, applications and functions of conservation patch. Based on land use type, soil type, slope grade, vegetation type and soil and water conservation measures, conservation patch is further explained. On this basis, this paper puts forward the construction technology of conservation patch, and establishes a set of management units of soil and water conservation. And it realizes the integrative application and management of basic data units of monitoring and evaluation of soil erosion, comprehensive harness of soil and water loss, supervision and law enforcement etc. The definition of conservation patch unifies the basic management and enhances the modern management of soil and water conservation.