A method for forming the gate structure of the NAND memory, comprising the steps of disposing a gate structure layer, a pattern transfer layer, a TEOS structure, and an organic dielectric Tri-Layer on a substrate sequentially; performing a patterning using a first photomask and a first photoresist layer; performing an etching process to form a control gate structure, a peripheral gate structure and a select gate structure; performing a trimming process to them; patterning sidewalls on sides of them; performing a second patterning using a second photomask as a mask and a second photoresist layer to protect the peripheral gate structure, the select gate structure, and their sidewalls; removing the control gate structure between its sidewalls; performing etching by using the sidewalls, the peripheral gate structure and the select gate structure as masks to form the control gate, the peripheral gate, and the select gate.