The role of river in the global water cycles and the modelling the horizontal water transport by rivers in the global scale are discussed. Due to the consolidation of the various hydrological information of the planet, now it is possible to monitor and simulate the quantity of the water carried by rivers. Land surface models that were developed originally for giving the boundary condition of the atmospheric and/or climatic models can be fairly used for river runoff simulations at least monthly scale, and it is promissing the approach will be a powerful tool to investigate the future water resources management.