Abstract: The effects of dangerous postures on workers musculoskeletal injuries in coal preparation plants during dirt extraction are discussed. By questionnaire survey and Ovako working posture analysis system (OWAS), the proportion of workers repeated harmful postures and physical damages are assessed and analyzed. The result shows that proportion and degree of harmful postures on workers back and neck are much higher, which is consistent with the result of fatigue selfconscious symptom survey and OWAS system analysis. Taking proper work shifts and increasing seats and protective devices may lower degree of workers musculoskeletal injury, improve performance in the workplace and reduce the occupational injuries and accidents.