At present a lot of air conditioning cooling water systems suffered serious bacterial contamination, especially the legionella to human health caused great threat. We have to pay attention to this problem.In this paper, some research achievements of how to control this water pollution at present are introduced such as physical and chemical methods. There are many methods that lack of comparative study. We had a sterilizing experiment for the air conditioning cooling water through ultraviolet rays sterilizing and fiter membrane sterilizing which...