1. A multi-level cell copyback program method in a non-volatile memory device comprising: reading LSB data of a source page, and storing the read LSB data in a second register of a page buffer; transmitting the data stored in the second register to a first register coupled to a data inputting circuit, and storing the transmitted data in the first register; amending the data stored in the first register through the data inputting circuit; transmitting the amended data to the second register, and storing the transmitted data in the second register; and LSB-programming corresponding data to a target page in accordance with the data stored in the second register.