Isothiazolin ketone is an efficient broad-spectrum biocide, suitable in the formula of complex corrosion inhibitors alkaline water treatment.It was mainly elaborated the technology of isothiazolin ketone with whole phosphine complex inhibitor in the circulating cooling water system of basic recipe,and its synergism of phosphine inhibitor, the negative impacts on the zinc component and process adjustments for reducing these impacts. It is pointed out that the technology of compound inhibitor with different components ,compound inhibitor and isothiazolin ketone should be further optimized,the content of different components,compound inhibitor,the technology should be used in the actual production in order to maximize the effectiveness of the two kinds of agents, improve economic use value of the agent .