Cesium lead halide perovskite nanocrystals (CLHP NCs) have drawn considerable attention because of their promising optoelectrical properties. However, owing to the extreme vulnerability of CLHP NCs to water and polar alcohols, until now most synthesis approaches inevitably adopted ecounfriendly solvents. It is still a challenge to employ green polar alcohol (ethanol) as a solvent to synthesize CLHP NCs. In this work, we realized the room-temperature in situ synthesis of CsPbBr3/SiO2, sol entirely in ethanol by innovatively constructing amine-functionalized silica micelles, which originated from the synergistic effect of 3-aminopropyltriethoxysilane and tetraethylorthosilicate (TEOS) during an acid-catalyzed sol-gel process. The sol exhibited high stability and an absolute photoluminescence quantum yield of 61.9% in ethanol without a further modification process. The light-emitting intensity of the sol preserved for 34 days merely declined to 62.1%. This work sheds light on the less common strategy of directly synthesizing CsPbBr3 NCs and long-term stable preservation in a strongly polar solvent.