Abstract: Diatom blooms outbreak occur frequently due to human activity and global warming, leading a negative impact on water ecology and water supply. Series of studies on freshwater diatom blooms have been published with a lack of summarization about the cause and control methods. The key factors in the outbreak of freshwater diatom blooming includes temperature, light, nutrient salts and flow rate. For the in-situ prevention, water scheduling and water aeration are well established and have a higher control efficiency of diatom blooming, while the effects of chemical technology treatment and biological strategies are not satisfied due to the environmental limitation. For water plant control, it is efficient to remove diatoms through the combination of coagulants and coagulant aids or oxidants. The expansion of the diatom bloom will lead to the failure to adjust the process in time, affecting the efficiency of water production. It is of great significance to understand the cause and control methods of freshwater diatom blooming for further ensuring drinking water safety.