The tacit knowledge theory of Micheal Polanyi is rich in connotation and extension. It is of great significance to understand the knowledge and technology that illustrates tacit root of articulating knowledge and the practical character of tacit knowledge. China's current agricultural technology popularization is facing dilemma, which are perceived evidently among the farmers and the science popularizers. From the perspective of epistemology, the lack of clear understanding of the essence of agricultural technology popularization is a major cause of the dilemma. In order to get out of the current “dilemma”, the following ideas can be used for reference: 1) Rethinking the three main subjects of agricultural technology popularization and their relation; 2) Fully recognizing the tacit attributes and priority of agricultural technology popularization; 3) The application of tacit knowledge in the development, promotion and acquisition of agricultural technology.