In this paper，we studied the online hot words and popular sentences in 2015. These words and sentences can be divided into 6 types，and the characteristics included the following：the disseminating periods of those hot words and popular sentences originating from breaking news were relatively short，while those originating from disasters became hot again when authorities released the results of the investigation；the superstars and opinion leaders as well as WeChat games played an important role in the disseminating of hot words and popular sentences；some hot words and popular sentences have been noticed by the government and as a result helped to improve the related policies；a great number of companies planned and conducted their promotion activities by taking advantage of the disseminating of hot words and popular sentences；some hot words and popular sentences reflected and satirized the society；their dissemination also showed some specific personalities and the spirit of creativity.