The type-2 fuzzy set is a set produced by expanding the membership function of fuzzy set into the type-1 fuzzy set. With the advantage of expressing deeper uncertainty, it is able to greatly enhance the description of uncertainty in the objective world. Therefore, the research on decision-making theories and methods in the type-2 fuzzy environment has been booming in recent years. This paper systematically surveys type-2 fuzzy decision-making theories and methods, sorts the development of this field, clarifies the research trend of existing work, and summarizes the main research results of type-2 fuzzy information aggregation and decision-making. Firstly, the development process and fundamental theory research of the T2FS are introduced. Then, the research status of decision fundamental theories(information fusion theory, preference relation theory and measure theory) and decision methods based on type-2 fuzzy information are summarized respectively. Finally, prospects of future research directions of type-2 fuzzy decision-making theories and methods are presented.