A data erasing method applied to a flash memory, comprising: receiving a data erasing instruction, wherein the data erasing instruction instructs to erase data, characterized in that the data corresponds to at least two data sections which comprise a latest data section, storing a data section that is last written, and a historical data section, storing a data section written before the latest data section; and erasing, according to the data erasing instruction, a data section that needs to be erased and that is among the at least two data sections corresponding to the data; wherein each of recorded storage addresses of all the at least two data sections corresponding to the data comprises a logical block address, LBA, and a block number, BN; the recorded storage addresses of all of the at least two data sections corresponding to the data are searched for, by using a map table, recording storage addresses of latest data sections, and a trace log, recording storage addresses of historical data sections; and all of the at least two data sections corresponding to the data are erased according to the storage addresses that are found; wherein the erasing a data section that needs to be erased and that is among the at least two data sections corresponding to the data comprises: determining, according to a BN in a storage address of the data section that needs to be erased, a data block in which the data section that needs to be erased is stored, and determining, according to an LBA in the storage address of the data section that needs to be erased, a page in which the data section that needs to be erased is stored; and searching for and erasing, according to the determined data block and page, the data section that needs to be erased, wherein the erasing comprises: re-writing the data section that needs to be erased at least once in an incorrect manner or a disordered manner, and then erasing the re-written data section. receiving a data erasing instruction, wherein the data erasing instruction instructs to erase data, characterized in that the data corresponds to at least two data sections which comprise a latest data section, storing a data section that is last written, and a historical data section, storing a data section written before the latest data section; and erasing, according to the data erasing instruction, a data section that needs to be erased and that is among the at least two data sections corresponding to the data; wherein each of recorded storage addresses of all the at least two data sections corresponding to the data comprises a logical block address, LBA, and a block number, BN; the recorded storage addresses of all of the at least two data sections corresponding to the data are searched for, by using a map table, recording storage addresses of latest data sections, and a trace log, recording storage addresses of historical data sections; and all of the at least two data sections corresponding to the data are erased according to the storage addresses that are found; wherein the erasing a data section that needs to be erased and that is among the at least two data sections corresponding to the data comprises: determining, according to a BN in a storage address of the data section that needs to be erased, a data block in which the data section that needs to be erased is stored, and determining, according to an LBA in the storage address of the data section that needs to be erased, a page in which the data section that needs to be erased is stored; and searching for and erasing, according to the determined data block and page, the data section that needs to be erased, wherein the erasing comprises: re-writing the data section that needs to be erased at least once in an incorrect manner or a disordered manner, and then erasing the re-written data section.