Abstract: To enhance the comprehensive prevention, control, and emergency response capabilities for forest and grassland fires, aiming to reduce the occurrence of such fires and achieve rapid dynamic monitoring of fire situations, the keypoint is lying on developing the information-based intelligent theories and methods for fire monitoring and early warning by integrating remote sensing, geospatial information, computer technology, fire ecology, and other disciplines. Based on the methods including remote sensing quantitative inversion of fuel variables and spatiotemporal big data mining, the technology system of remote sensing monitoring and early warning for forest and grassland fires for the pre-fire/during fire/post-fire period is established. It mainly includes the fire risk forecasting and early warning technology incorporating multisource spatiotemporal big data on fuel, weather and topography variables, the rapid and high-precision fire detection technology based on multisource satellite data, and the technology of accurate burn severity estimations. In response to the practical applications in southwestern China, the customized system for forest and grassland fire monitoring and early warning is developed, involving the key methodologies and technologies of fire monitoring and early warning. This system could achieve functions of fire risk early warning, near-real-time fire monitoring and fast assessment of fire loss. It also provides convenient and efficient dynamic information services for forest and grassland fire monitoring and early warning, and shows the significant practical application effectiveness, indicating the potential for its widespread adoption.