Abstract: An experimental investigation for determining the discharge coefficient of jet impingement holes within semi-enclosed channel was performed.According to the jet impingement configurations with single row or double row holes,the effects of the holes arrangement and flow parameter on the discharge coefficient were considered,such as: the span holes pitch-to-diameter ratio,the streamwise holes pitch-to-diameter ratio,the impingement distance-to-diameter ratio,the jet oblique angle and the jet Reynolds number.Comparatively,the above factors on the discharge coefficient were discussed.