工程签证集政策性、技术性、经济性于一身,既是合同管理的重要组成部分,也是施工阶段投资控制的重点,还是司法实践中索赔与反索赔争议的焦点。文章重点围绕工程签证管理中的三种常见问题和实践中存有争议的三类签证效力认定,给出了司法实践对于工程签证效力的认定标准,并提出了完善工程签证管理的两大具体对策。工程签证,是指在施工合同履行过程中发、承包双方就合同价款之外的费用补偿、工期顺延以及因各种原 Engineering visa set policy, technical, economic in one, is not only an important part of contract management, but also the focus of investment control during the construction phase, or judicial practice claims and anti-claims dispute focus. The article focuses on three common problems in project visa management and the validity of the three types of controversial three kinds of visas in practice. It also gives the recognition standards of judicial practice on the validity of project visas and proposes two specific measures to improve project visa management . Project visa, refers to the construction contract in the process of fulfillment, both parties to contract costs compensation for the contract, the duration of the delay as well as the original