Abstract: The shock wave overpressure, heat flux intensity and gas jet impulse during the firing of weapon system were tested to evaluate the risk in the back-ejection area of recoilless rifle. Based on the analysis of the test data and the calculation of the probability model, the personnel trauma probability under the action of different dangerous sources was obtained. The results show that shock wave could cause injury to human eardrum and lung tissue in the dangerous area with a radius of 5 m and a fan angle of 120 degrees. The degree of injury is the most serious in the rear of nozzle. The probability of lung tissue injury is more than 50% in 2 m. The diameter of flame zone is about 2.18 m, and the heat flux in the center of fireball is the strongest. The probability of first-degree burn is 46.95%, but it is not lethal enough. The gas impulse produced by the high-speed gas jet is lethal to the human body, especially when the human head is impacted, the distance of fatal probability greater than 50% is 3 m. Key

Key words: recoillessrifle, back-ejectiondangerzone, riskevaluation, traumaprobability