The invention discloses a thermodynamic calculation method of non-freezing ranges of water flow in cool regions during water injection and ice melting. According to the method, a heat balance theory of water flow is adopted to deduce a computational formula of the nonfreezing range of a water guiding channel and analyze the influences on the non-freezing ranges under different waterpower, heating power and weather conditions, in order to provide theoretical reference for application of techniques of water interjection and ice melting in diversion-type hydropower stations in the cool regions; overall influences caused by different factors including the water power, the heat power, the weather and the like are taken into account; according to meteorological data, hydrologic data of power stations and the other data of each region, by using the thermodynamic calculation method, different non-freezing ranges during water interjection and ice melting can be calculated; the method is not only suitable for application in water flow with different flow quantities and flow velocity, but suitable for calculation of the non-freezing ranges under the conditions of different outer atmospheric temperature, wind speed and the like; since all the influence factors are taken into account in the thermodynamic calculation method, the application range is much wider.