不等式的证明经常出现在高考及各级竞赛之中,其中很多不等式用常规方法很难证明,常常需通过构造的方法来进行证明,本文现就此介绍一些常用技巧. Proof of inequality often appears in the college entrance examination and competitions at all levels. Many of the inequalities are difficult to prove by conventional methods, and often need to be proved by constructive methods. This article introduces some commonly used techniques.