This paper summarized the principles of CFCC standards related to natural forest quality,measuring from 4 aspects of natural forest,namely authenticity,growth vitality,structure stability and health status,outlined the function mechanism for improving quality of natural forest from 5 aspects,including forest management plan formulation,land protection,tending and regeneration,disaster prevention and control,and financial support,and evaluated the actual effect by a case study of Baihua Forest Farm in Xiaolongshan,Gansu Province.The results showed that forest certification improved the quality indicators of natural forest,namely area,volume,age structure,forest coverage,etc.Some suggestions were put forward,such as establishing the coordination mechanism between the government departments of natural forest protection and forest certification,setting up special funds to support natural forest certification,giving priority to promoting the forest management certification,and establishing the certification through green channed.