We elaborate relevant theories of farmers’ relational network, including the Differential Model of Association, the Strength of Weak Tie, Strong Tie Strength, and Favor and Face. The farmers’ relational network in the Differential Model of Association can be divided into three layers: strong tie, weak tie and irrelative relationship according to theory of Granovetter. These three layers have deep influence on opportunity selection during undertaking, financing and enterprise development. With rational knowledge of these layers, farmers may exploit undertaking resources. On the basis of this, we made detailed analysis on farmers’ selection of relations in the opportunity selection, financing and enterprise development stages.