Flash evaporation is widely used in industrial application, such as desalination. An experimental device has built to study the flash evaporation of pure water. The flash experiments were carried out with an initial water height of 0.44 m, initial temperature ranging from 50 °C to 98 °C, and superheat between 4 K and 15 K. The influence of initial temperature on flash evaporation was analyzed. Results suggested that increasing the initial temperature could accelerate the water temperature drop of flashing process, and the evaporated water mass increases with the initial temperature. The study could provide further theoretical support for flash evaporation in industrial applications. © 2018 Institute of Physics Publishing. All rights reserved.