The present invention discloses a flash memory and a method for fabricating the same, and relates to the technical field of the semiconductor memory. The flash memory includes a buried oxygen layer on which a source terminal, a channel, and a drain terminal are disposed, wherein the channel is between the source terminal and the drain terminal, and a tunneling oxide layer, a polysilicon floating gate, a blocking oxide layer, and a polysilicon control gate are sequentially disposed on the channel, and a thin silicon nitride layer is disposed between the source terminal and the channel. The method includes: 1) performing a shallow trench isolation on a SOI silicon substrate to form an active region; 2) sequentially forming a tunneling oxide layer and a first polysilicon layer on the SOI silicon substrate to form a polysilicon floating gate, and forming a blocking oxide layer and a second polysilicon layer to form a polysilicon control gate; 3) etching the resultant structure to form a gate stack structure; 4) forming a drain terminal at one side of the gate stack structure, etching the silicon film at the other side of the gate stack structure, growing a thin silicon nitride layer, and then refilling the hole structure with silicon material, to form a source terminal. The method has the advantages of high programming efficiency, low power consumption, effectively preventing source-drain punchthrough effect.