A method for reading a memory, which includes a memory cell having a first half cell and a second half cell, includes the following steps. A first voltage is applied to the memory cell to determine whether a threshold voltage of the first half cell is higher than a predetermined value or not. If the threshold voltage of the first half cell is higher than the predetermined value, a second voltage higher than the first voltage is applied to the memory cell to read data stored in the second half cell, otherwise a third voltage lower than the first voltage is applied to the memory cell to read the data stored in the second half cell.