A method for preparing an SOI wafer by using rapid thermal processing includes: taking a silicon wafer as a raw material, sequentially performing process steps of oxidation, H+ implantation and bonding to obtain a bonded wafer with an H+ implantation layer; and then splitting the bonded wafer by using rapid thermal processing and microwaves to obtain a required SOI wafer. In the present invention, an SOI film after wafer splitting has better thickness uniformity and lower roughness. The present invention may improve lattice damage after implantation and reduce SOI surface defects after wafer splitting and thus improve the SOI surface quality. The present invention is high in wafer-splitting speed and thus reduces silicon wafer contamination. The present invention has high efficiency and an excellent comprehensive technical effect.