We show that the existence of external control system would enhance the monitoring function of the internal control system, and as a result restrain the moral hazard behaviors of the entrepreneur.

When LPG tanks are exposed to external fire, their temperature and pressure will increase rapidly, which may cause the tanks exploding and lead the secondary hazard with much more damage.

At last, with the analysis of factors of external environment, this paper puts forward entropy measure method of moral hazard problem of the whole supply chain system.