Abstract: On the basis of water quality analysis data, the type and degree of scaling of every waterflood system in Dagang Oilfield are separately studied using water quality analysis software and chemical analysis method, and the accuracy of result predicting is proved, comparing the actual result of sample analysis. Every element that influences the scaling of every waterflood system is also researched by the system, series of conclusions are obtained regularly and the dominant elements that cause the scaling are revealed. It can offer the theory basement for handling injected water quality using the adequate scaling inhibiting measures and reducing the degree of scaling and maintenance cost of waterflood pipes, and has an important instructing significance for oilfield production.