The paper proposes a statistical method of headcount based on machine vision technology, which is implemented in quota management in dangerous production place. The head’s region is extracted roughly with hair color feature and regional growing algorithm. And then, the head region is matched by the mean of circle contour. Obtaining a series of continuous frame images, target tracking can be realized. The detail is that moving forecasting function is set assisting to obtain head's moving trajectory. So whether the people enter or leave production place can be judged according to trajectory. Finally, the experiment proves the practical effectiveness and academic value of the method, the accuracy can reach 90% above. It is also very significant for safety in production.