An EEPROM device, a forming method thereof, and a method for implementing an erase operation to the device are provided. The EEPROM device includes: a semiconductor substrate having active regions therein; a word line disposed on a first active region; float gate dielectric layers disposed on second active regions; float gates disposed on the float gate dielectric layers, wherein each of the float gates has a width larger than that of the second active region; control gates disposed on control gate dielectric layers which are disposed on the float gates; an isolation oxide layer disposed between the word line and the float gates along with the control gates; and bit line doping regions disposed on third active regions. Accordingly, an erase operation can be implemented from a bit line, and coupling ratios of a float gate to a control gate and to a bit line doping region can be improved.