Any insurance product must pass the test of legality by both departments of judiciary and legislature before it can enter the market. Despite this, insurance disputes are still rife in Taiwan; judicial testing, hence, has become an important issue for the insurance study. Judicial testing can be divided into two areas: content control and explicatory principles. In this thesis, I focus on judicial control. I intend to start with the discussion of insurance theory from which the nature of insurance is conferred; I proceed to construct a regulatory overview of prohibitive provisions in the insurance law. The discussion is complemented with verdicts from judicial practices from which I discuss how the explicatory principles of articles in insurance contract are put into judicial practice in Taiwan, and I advise the way these principles should be applied.