Abstract: To explore the energy flow, control ways, benefits of the “pig-biogas-grain” circular agricultural mode, and whether it is suitable for popularization in Guanzhong plain, we analyzed the energy input and output, energy flow direction, energy circulation index and the benefit of this mode by the energy flow theory and system analysis method. The results showed that this circular mode was an environment-friendly agricultural production mode which mainly focused on pig breeding together with straw returning and biogas engineering. The input energy of this system was mainly organic, the ratio of solar energy utilization of crop was 1.19%, and the index of energy cycle was 0.92, with a high stability and self-maintenance ability as well as a high mechanization degree. The income of farmers would increase 7149.78 yuan every year with the practice of this mode, and ecological and social benefits would also be enhanced. But the low cropping index and low science technology investment leaded to the low ratio of energy output-input. The cycle model is suitable for Guanzhong area, the principle of restructuring and optimization according to the local conditions should be taken, and the developmental strategy of agricultural technical guidance department should be improved when the mode is applied.