The article not only aims at illustrating the phenomenon of and reasons for why insurers misuse promissory warranties in insurance policies, and Supreme Court frequently has hardship on differentiating promissory warranties from other types of terms in insurance contracts, such as excepts or conditions, but also provides some solutions in respect of regulation and contract interpretation for judges and regulators. In practice, insurers tend to use ambiguous and vague context in order to garner unfair benefits either on pretext of other types of terms in policies by the title of warranties, or by harnessing technical words to transform exclusions into promissory warranties. What’s even worse, the Supreme Court of Taiwan is inclined to interpret these disguised or equivocal terms in a formalistic fashion, as triggers unpredictable and unstable results. As a consequence, both practical blurred warranties and judicial formalistic interpretation give rise to unnecessary trade costs probably impeding insurance trade. The author figures out two approaches to mitigate the problem: one is through screening mechanism of insurance products exercised by regulators to delete ambiguous and problematic terms in advance; the other is via special principles of interpretation set forth in Article 54 of Insurance Act and Article 11 and 12 of Consumer Protection Law.