The research of the variability of a speech genre ”Diary” shows the presence of five basic models built on the following features: belonging to one of the basic worldviews, the type of mental space, the type of the concept forming the genre, the type of a modal subject, the reference towards reality, speech strategy and the genre format. The connection of linguistic, cognitive, psycholinguistic indicators allows to work out an izosemical model and build a table showing the modification process of the hypergenre ”Diary”, which coincides with a historical analysis of the chronology of the formation of its variants in Russian culture, thus testifying to a possibility of using this analysis as a method of the genre's reconstruction.