The technology of summarizing documents automatically is increasing rapidly and may give an answer for the information overload quandary. These days, document summarization is assumed an imperative part of information retrieval. With expansive amounts of documents, giving the user a short version of every document incredibly encourages the errand of discovering required documents. Text summarization is a procedure for making a packed form of a particular document that gives the users utilizable info, and summarization of multi document is engender summary distributing the meaning of the most info either explicitly or implicitly from a group of documents about main topic. In text summarization, resemblance among several sentences in a text has a major role. As such, development of methods of summarization has taken into consideration the aspect of similarities between several sentences in a text. This paper seeks to investigate different techniques of automatic summarization based on t