Abstract: Accurate river runoff simulation is of great importance for basin hydrological simulation, water resources plan and sustainable management, hydrological disaster prevention and control. With the rapid development of the earth observation satellite remote sensing techniques, microwave remote sensing monitoring can provide a new method for river runoff simulation. To date, for river runoff simulation, further exploration is needed based on passive microwave remote sensing brightness temperature observations. This paper applied the M/C signal method to river runoff simulation in typical river basins in China based on a high-resolution passive microwave remote sensing brightness temperature dataset. The usability of this method was discussed. To analyze the influence factors of the simulation results, 7 geomorphologic and hydrometeorological factors were chosen, including river width, mean observed discharge, control area, vegetation percentage, elevation, land use/cover and climate type. Results of the monthly runoff simulation show that among the 61 typical sites in 7 river basins in China, R² of 59.0% of them exceeded 0.5 and more than 41.0% reached an E_NS larger than 0.5. Performance for the sites in basins of the rivers in Southwest China is obviously better, especially for the sites on the Tibetan Plateau; elevation, mean observed discharge, climate type and width of the river cross section are found out to be the dominated factors; and the M/C method is more suitable for sites on small rivers of high elevation under mountain plateau climate. Generally, this paper can inspire research ideas for river runoff simulation, thus providing reliable guidance for extending the hydrological application of microwave remote sensing in China.