Abstract: A method for preparing a recessed transistor structure comprises the steps of performing an implanting process to form a doped layer in a substrate, forming a plurality of gate-isolation blocks on the substrate, forming a plurality of first spacers on sidewalls of the gate-isolation blocks, removing a portion of the substrate not covered by the first spacers and the gate-isolation blocks to form a plurality of depressions in the substrate between the first spacers, forming a gate oxide layer on inner sidewalls of the depressions, and forming a gate structure on the gate oxide layer to complete the recessed transistor structure.