Abstract: The judges may face two or more legal norms when they select the applicable legal norms, between which may exist such relationships that are superior position law and lower position law, special law and common law, new law and old law from different angles, thus the judges will face different legal applicable principles when two or more principles are both applicable. The paper argues that the judges should comply with certain logical and legal standards, so they can make the correct judgments and adopt the right legal principle.