Abstract: Natural forest is the most important forest resources, and natural forest protection is the key part of sustainable development of forestry in China. As a famous silviculturist and forestry educator, Professor SHEN Guo-fang has been committing to the theory and technology exploration of sustainable development of forestry in all the time, he is an active advocator and facilitator of Natural Forest Protection Project (NFPP) in China, and has systematically expounded the theories and methods of natural forest management. There are three periods of his understanding on natural forest protection, by which a theoretical system covering five major sectors of guiding ideology, management methods (thinking), related technologies, policies and disciplines is formed. He believes that natural forest has a critical status in the construction of ecological environment in China, and the protection of natural forest is a key part of national ecological civilization construction. The natural forest has different characteristics from planted forest, such as uneven age, complex structure, and adaptation of the environment. Natural forest protection should be guided by the sustainable development of forestry, in which some basic techniques should be learned from forest cultivation and protection, and the multi-disciplinary system is taken as the technical support, so as to not passively protect the natural forest. These views result in the profound and positive influences on the healthy development of natural forest protection in China.