Sentiment analysis or Opinion Mining is rapidly growing area, in which Sentiments or opinions of customers gathered, analysed & aggregated from text. There several algorithms are available for sentiment analysis. The collected data is pre-processed first & then algorithms are applied on it for polarity detection. Review sites, ecommerce sites collects reviews which needs to be analysed and can identify various analysis on sentiments expressed on those reviews. This paper surveys different methods on sentiment analysis referencing various authors’ publications.