At present，the traditional scale weighting analysis method which also was called weighting compatibility test could only evaluate the weight of scale but lacking of approaches and standards for quantitative scaling degree evaluation. In order to improve the traditional scale weighting analysis method，the scaling type and scaling degree were evaluated from the two aspects of qualitative and quantitative study. The basic concepts like suspended scale，settling scale and total scale were proposed，and the parameters and standards for scaling degree evaluation of injection water and formation water were established. Taking injection water of Guantao group and formation water of Minghuazhen group in BZ28-2 south oilfield as the research object，the types and content of scale were studied by several approaches such as X-ray diffraction analysis（XRD），scanning electron microscopy （SEM）and optical microscopy analysis（OP）. The results showed that the injection water and formation water in BZ28-2 south oilfield were seriously incompatible and the comprehensive evaluation index of fluid compatibility degree was 3.33. The comprehensive evaluation index of the scaling degree was 3.87 and the scaling degree was medium to strong，which was easy to generate CaCO₃ scale. The measured total scale was from 27.5 to 94.0 mg/L，and among which the settling scale was predominated. In addition，the scale was the most serious when the volume ratio of injection water to formation water was 1∶1. The scaling degree evaluation method was both scientific and objective，which could be applied to evaluate the scaling degree among various fluid types in oilfield.