Flash memory device with a function for changing selectively voltage for precharging sensing node and read operation method of the same

A flash memory device and a data reading method thereof are provided to reduce the number of failures in a reading process by mitigating signal interference between sensing lines. A flash memory device includes a memory cell array(110), a precharge voltage generator(120), and plural page buffers(PB1-PBN). The memory cell array includes plural memory cells, which share plural word and bit lines. The precharge voltage generator outputs one of the first and second voltages as a precharge voltage in response to a selection control signal. The page buffers are connected to at least one pair of the bit lines and precharge the sensing lines with the precharge voltage in response to a precharge control signal. During a verification process or a normal process of the flash memory device, each of the page buffers detects the read data, which is transmitted from one of the memory cells to one of the sensing lines through one of the bit lines.