Abstract: The forest site productivity (present forest productivity,intensive managed forest productivity and potential forest productivity) and forest suitability (or limitedness) are form the basis for site classification. There are four principles for forest site classification:1.identification of physical forest site factors and its group;2.similarity of forest site productivity and forest suitability;3.identification of factors,on which forest site is formed and limiting factors;4.identification of developing stage of forest site and forest management direction. The system of forest site classification is composed of forest site region,forest site district,forest site class,forest site type group,forest site type and plant association type.