This is a pedagogical review on deformation of two dimensional quantum field theories. It is based on three lectures which the author gave at ITP-CAS in December 2018. This review consists of four parts. The first part is a general introduction to deformation. Special emphasises are put on the deformed classical Lagrangian and the exact solvability of the spectrum. The second part focuses on the torus partition sum of the / deformed conformal field theories and modular invariance/covariance. In the third part, different perspectives of deformation are presented, including its relation to random geometry, 2D topological gravity and holography. We summarize more recent developments until January 2021 in the last part.

这是关于二维量子场论变形的教学评论。它基于作者于 2018 年 12 月在 ITP-CAS 上的三场演讲。本综述由四部分组成。第一部分是对变形的一般介绍。特别强调变形的经典拉格朗日函数和谱的精确可解性。第二部分侧重于/变形共形场理论和模不变性/协方差的环面划分和。在第三部分中，提出了变形的不同视角，包括其与随机几何、二维拓扑重力和全息的关系。我们在最后一部分总结了 2021 年 1 月之前的最新进展。