Aiming at the problem of unclear mechanism of fuel consumption factors of heavyduty fertilizer spreader under ‘human-vehicle-soil’ operating system and the problem of ‘power supply abandonment’ caused by short single operation period and low frequency of operation cycle of agricultural machinery, the interaction mechanism of fuel consumption structural equation model of ‘human-vehicle-soil’ system was analyzed and the gain potential of ‘one source for multi-purpose’ mode of pure electric tractor power supply to ‘life-ecology’ was predicted. Firstly, a comprehensive field test of heavyduty tractor spreading fertilizer operation was carried out, and the data of operation factors such as driver fatigue, tractor fuel consumption and plough layer soil characterization were collected, and the fuel consumption structural equation model of human-vehicle-soil layer was established. Then based on the causal relationship of structural equation, the correlation between agricultural machinery fuel consumption factors was explored. Finally, based on the equivalent conversion theory of fuel consumption, the equivalent power demand and carbon emissions of fuel agricultural machinery were calculated, and the contribution potential of the ‘one source multi-purpose’ mode of pure electric tractors to the exchange and sharing of production and living power sources and emission reduction and carbon reduction was predicted. The results showed that the soil compaction was the main fuel consumption factor of tractor. The driver’s operating fatigue had an indirect effect on fuel consumption, which can indirectly affect the physical properties of the plough layer and the carbon emissions and operating efficiency of the tractor by manipulating the tractor. The electric tractor power supply ‘one source multi-purpose’ had certain potential for power supply to small power facilities at the end of the agricultural network. During the mechanized field management period, the equivalent power consumption was about 45kW·h/hm2, reducing carbon emissions by 12kg/hm2(CO2). Small and medium-sized farms can reduce the carbon emissions of agricultural machinery by about 2464 tons of CO2, saving 9.24×106kW·h electricity, and providing about 110 tons of electricity required for corn drying when the power supply was idle, or the power required for ventilation for 165 sets of ventilation equipment at the same time throughout the day, or 5500 street lights for night lighting, or the annual electricity demand for 11 duty rooms.