Innovation can enhance the usefulness of products and services, but technological innovation may be hindered by many potential barriers. One important potential barrier is patent infringement, whose risk must be evaluated and quantified when a firm works on innovation. Previous studies have focused on patent quality, patent value, and the use of patents as indicators of company competitiveness, but to our knowledge there have been no previous studies discussing the evaluation or forecasting of patent infringement risk. To address this issue, we conduct a knowledge management study to reexamine the relationship between patent quality/value and patent litigation, identify patent risk factors, and build a regression model for evaluating patent infringement risk. We make two important discoveries during the course of this study. First, we found that certain factors do not hold significant amounts of impact in all technological fields. Second, we discover that the same factor may not have the same impact in differing technological fields.