Abstract: Based on symbiosis theory, Lokta Volterra dynamic model for symbiotic evolution of two entities, a managed farmer and a managed service organization, was constructed to explore equilibrium results of symbiotic evolution of two entities under different symbiotic coefficients．On this basis, numerical simulation was used to simulate symbiotic evolution mode of two entities．Research results indicated that under different symbiotic environments, entrusted farmers and entrusted service organizations would form three symbiotic modes: parasitic symbiosis, biased symbiosis, and reciprocal symbiosis, and these three modes had dynamic evolution characteristics．Equilibrium result of symbiotic evolution between entrusted farmers and entrusted service organizations depended on symbiotic coefficient．Trusteeship farmers and trusteeship service organizations could only achieve optimal development state under a mutually beneficial symbiotic model．Based on model results, corresponding policy recommendations were proposed．