The invention discloses a nonvolatile memory erase method and a nonvolatile memory erase device. The method comprises the steps that: a target erasing target is subjected to a preprogramming operation, wherein the preprogramming operation is that 0 is written into memory units of the target erase object; whether the preprogramming operation is successful is examined, wherein the examining is that whether currents of the memories in the target erase object processed through the preprogramming operation under a certain gate voltage are all smaller than a target current value which is a current value with current margin; if the preprogramming operation is successful, a next step is executed, and if not, the progress is turned back to the execution of the preprogramming operation; the target erase object is subjected to an erase operation, wherein the erase operation is that 1 is written into memory units of the target erase object; and the target erase object is subjected to an over-erase examine operation, wherein the over-erase examine operation is that threshold voltage of memory units in the target erase object is adjusted. With the method and device provided by the invention, nonvolatile memory erase speed can be improved, and memory performance can be improved.