The increasing quantity of the combines is the main factor of the decreasing profit in transregional wheat harvesting. A system dynamic model of trans-regional harvesting has been built to analyze the system. The result of simulation shows that the increase rate of buying combines and the increase rate of traveling combines go up rapidly at first, and then decrease to a steady-going level. Based on the result, it pointed that the standard services and supervision system is the key factors which keep trans-regional wheat harvesting energy, information service system need to reinforce farther. Government should change direction of main subsidy on agricultural machinery. It is important to optimize the structure of machine resource for the smooth development of trans-regional harvest.
