A method for preparing a polishing pad includes: preparing a polishing pad transition structure formed with a plurality of grooves, openings of the plurality of grooves being all located on a same side surface of the polishing pad transition structure; filling the plurality of grooves of the polishing pad transition structure with inorganic nanoparticles; pouring a mixture of a liquid polymer and a curing agent on the polishing pad transition structure, and evacuating air in the liquid polymer and the plurality of grooves; and placing the polishing pad transition structure in an environment at a temperature higher than or equal to a first temperature threshold, and the cured liquid polymer and the polishing pad transition structure constituting the polishing pad.