The diversity of diatom flora of river Narmada at district Harda, (M. P.) for the period of one year from in July 2015 to June 2016 have been studied. 16 genera and 45 species reported in river Narmada. During study it was found that taxa of diatoms are Fragilaria papillosa, Navicula cryptocephala, N. rostrata, Nitzschina obtuse, Gomphonema olivacem, Cymbella australica, and C. saffinis were found to dominated. The diatom population much fluctuates during the climate change. Population of diatom was decrease during the month of April to June due to the various abiotic factors which influence diatom. Light, temperature, turbidity and dissolve Oxygen are the most valuable factor for the growth of diatom.