In this paper , the GaP/Al2 O3/SiO2 guided light-emitting structure is used as the bonding layer of the chip , and the chemical mechanical polishing process is introduced to reduce the epitaxial voids in the transfer process of AlGaInP-based Mini-LED substrates to improve the chip preparation process yields. Using material removal rate and surface roughness as technical evaluation indexes , L9(34 ) orthogonal experiments were conducted based on the re- sults of single-factor experiments on polishing pressure , polishing head speed , polishing plate speed , and polishing fluid flow rate. The experimental results show that the material removal rate is 83. 12 nm/min and the surface rough- ness is as low as 0. 477 nm under the conditions of polishing head speed 75 rpm , polishing plate speed 80 rpm , polis- hing pressure 8 kPa and polishing fluid flow rate 100 mL/min. The optimized process conditions can obtain high quali- ty GaAs bonding surfaces , effectively reduce epitaxial voids , and improve preparation yields.