Nanostructured aluminum recently delivers a variety of new applications of the earth-abundant Al resource due to the unique properties, but its controllable synthesis remains very challenging with harsh conditions and spontaneously flammable precursors. Herein, a surface group directed method is developed to efficiently achieve low-temperature synthesis and self-assembly of zero-dimensional (0D) Al nanocrystals over one-dimensional (1D) carbon fibers (Al@CFs) through non-flammable AlCl₃ reduction at 70 °C. Theoretical calculations unveil surface ‒OLi groups of carbon fibers exert efficient binding effect to AlCl₃, which guides intimate adsorption and in-situ self-assembly of the generated Al nanocrystals. The distinctive 0D-over-1D Al@CFs provides long 1D conductive networks for electron transfer, ultrafine 0D Al nanocrystals for fast lithiation and excellent buffering effect for volume change, thus exhibiting high structure stability and superior lithium storage performance. This work paves the way for mild and controllable synthesis of Al-based nanomaterials for new high-value applications.