Copula functions can describe the complex dependence structure between variables comprehensively and flexibly, which make them widely used in finance. The dynamic development of financial markets causes the dependence structure between financial variables to change over time, which can be modeled by dynamic copulas by changing the parameters or type of copula function. This paper reviews systematically the main literatures on dynamic copula models and their applications in finance, from the development of dynamic copula models, several commonly-used dynamic copula models, and their main applications in finance. In the conclusion we present the summary and future research directions of dynamic copulas.