For anyone who wants to practice in maritime law, or to a wider extent, commercial law, the interpretation of contracts is a topic of vital significance.In the world of maritime contracts, no matter that they are charterparties or marine insurance contracts, a great number of disputes arise because different parties of the same contract have different explanations to the meaning of contracts. The courts therefore have responsibilities to use some principles to settle the disputes.Law school students usually do not exploit this important field, which may not be helpful for the development of these would-be lawyers. Fortunately, the learned judges, however, did not neglect this difficult but fascinating area. For hundreds of years, in hundreds of cases, they are keeping exploring it, formulating and creating numerous principles regarding the methods of interpretation. In this thesis, therefore, an attempt is made to set these principles out and discuss them with particular regard to maritime law.