Global hydrological models (GHMs) are important tools for addressing worldwide change-related water resource problems from a global perspective.However,the development of these models has long been hindered by their low accuracy.In order to improve the streamflow simulation accuracy of GHMs,we developed a GHM—the FLEX-Global—based on the regionalization of hydrological model parameters.The FLEX-Global model is primarily based on the framework of the FLEX hydrological model coupled with the HAND-based Storage Capacity curve (HSC) runoff generation module to calculate net rainfall,and uses the global river-routing CaMa-Flood model to calculate river network routing.This new model allows for streamflow simulation at a spatial resolution of 0.5°×0.5° and a temporal resolution of 1 day in global catchments.To validate FLEX-Global accuracy,the FLEX-Global-simulated streamflow of 26 major rivers distributed in five different climate zones was compared with the observed data from the Global Runoff Data Center (GRDC).Next,the model performance of FLEX-Global was further verified by comparing it with that of seven existing GHMs with varying accuracy in the five climate zones.Multi-metric evaluation indicated that the streamflow simulation accuracy was improved by the FLEX-Global model with regionalized parameters,especially in the tropical and dry climate zones.This newly-developed GHM with regionalized parameters can provide scientific support for the assessment of climate change impact,optimization of global water resource mangement,simulation of Earth's multi-sphere coupling,and implementation of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP).