A soft program method is provided for recovering memory cells of a memory array. In an embodiment, the method includes the following steps. Memory blocks of the memory array are soft programmed with first bias voltage. A selected memory unit within a selected memory block is then soft programmed with second bias voltage. Next, whether a judging criterion is met is determined. If not, the method is repeated from the step of soft programming with the second bias voltage; if so, whether the selected unit is a last memory unit is determined. If the selected unit is not the last memory unit, other memory unit is assigned as the selected memory unit and the method is repeated from the step of soft programming with the second bias voltage. When the selected unit is the last memory unit, the memory array is bit-by-bit soft programmed with a third bias voltage.