Meta–analysis is a new method of literature review, which is developed on the basis of traditional literature review. It is based on a specific design and some statistical methods. Different from the initial analysis, it is applied for further analysis of a systematic quantitative and qualitative analysis of the results of previous literatures review. Meta analysis is an improvement on the traditional literatures review. It is a retrospective and observational statistical method. It is also a comprehensive, quantitative and systematic statistical method for summarizing the results of previous studies. It can integrate the research results collected from different research designs, different research fields and different journals on the same subject. To some extent, this method can overcome the problems brought by the traditional literature review. But it has its own limitations. At present, meta–analysis has been widely used in different research fields in China. In this paper, the concept and theoretical basis of meta–analysis are briefly introduced. And the research steps of meta–analysis as well as its characteristics and limitations are described. In order to understand its latest progress, this paper analyzes its application in psychological literatures collected by the CNKI in the last five years.