Abstract: In future deep space exploration missions such as Mars sampling, manned landing on the moon, Jupiter system exploration, as the entry speed of the probe far exceeds the first cosmic velocity of the target planet, the system energy increases significantly This leads to extreme flow and heat transfer phenomena accompanied by ultra-high temperature physical and chemical reactions, involving complex interactions between microscopic physical and chemical reactions and macroscopic flows, heat and mass transfer at the fluid-solid interface, and internal thermodynamic response of thermal protection materials. How to accurately predict such an extreme flow and heat transfer system with multi-phase, multi-scale, multi-process and strong coupling characteristics, so as to support the precise design of the probe for efficient kinetic energy dissipation and effective heat isolation, poses a severe challenge to fluid mechanics and related disciplines. This paper focuses on the extreme flow and heat transfer during planetary atmospheric entry, discusses and sorts out the key scientific problems in three aspects: ultra-high-speed flow, intense radiation heat transfer and ultra-high-temperature physical and chemical reactions, and prospects future research in this field.