Based on the unbalanced relationship among modern population, resource and environment, as well as the weak awareness and supply-demand conflict of forest public product, the paper exposed the public product function of forestry and explained its meaning, then evaluated the traditional concepts of forestry, product, and forest products, and finally redefined the extension of forest products. On this basis, the concepts of forestry and public products were elaborated, and the connotation, characteristics and extension of forest public products were clearly defined and described.