A mechanochemical in-situ solid-state reaction synthesis method for Si-based composites was developed. This method involves milling excess micron-Si and Ag2O to form SiO and Ag particles in-situ and adhere to the matrix Si during the ball-milling crushing process (abbreviated as Si/( SiO + Ag )). Carbon-coated Si-based composites Si/( SiO + Ag ) - C were prepared using asphalt as a carbon source by high-temperature calcination. Both of these composites exhibit excellent rate performance, exhibiting reversible specific capacities of 1422 and 1039 mA h/g at low current density (0.12 A/g), respectively, while 672 and 393 mA h/g can still be obtained at high current density (2.4 A/g); When the current density is restored to 0.12 A/g again, the reversible capacity can be restored to 1329 and 961 mA h/g. In contrast, Si/(SiO + Ag ) - C exhibit better cycle stability, and their capacity remains stable above 943mA h/g after 80 cycles. This outstanding rate performance is attributed to the refinement of Si-based particles and the electrical conductivity of in situ-formed nano-Ag particles, while the improvement in cycle stability is related to the dual-phase buffer structure composed of in situ-formed SiO and coated carbon.