Abstract: The traditional method of obtaining theoretical losses of distribution networks based on time section information or average power as the boundary, using power flow calculation, cannot solve the impact of load spatiotemporal changes on calculation accuracy; The increasingly improved load side monitoring methods provide data support for improving the accuracy of theoretical loss calculation in distribution networks. Based on the correlation between the spatiotemporal distribution characteristics of load and network losses, this article designs a load curve shape coefficient that characterizes the time-varying nature of load, and introduces a power transmission complex efficiency that characterizes the spatial distribution characteristics of load; Taking into account the spatiotemporal distribution characteristics of load, a correction coefficient for the traditional distribution network theoretical loss calculation model based on power flow calculation has been constructed; This method can effectively improve the accuracy of network loss theoretical calculation results. The comparison of case analysis results proves the effectiveness of this method.