Abstract: Conception of man-machine system (man-machinery or man-semimachinery system and man-machine system with automation control) and 3-E Principle (Engineering, Education, Enforcement) is described.Implement manner of 3-E Principle in emergency accident induced from man's unsafe behavior is given.An actual case provided in Laocheng Gas Compressor Station, Hainan Province proves that effective application of man-machine system and 3-E principle can form a benign loop management system, which can strongly ensure safe operation management for the oil pump station and gas compressor station.