A method for implementing a dongle, comprising: a security chip of a dongle determining whether a secure digital (SD) card in a card slot of the dongle is a valid SD card; if the SD card is a valid SD card, when a received instruction is a first/second USB flash drive area access instruction sent by a system, executing an operation of accessing the first/second USB flash drive area; when the received instruction is a PIN code verification instruction for the second USB flash drive area or an encryption area sent by an upper layer, executing a PIN code verification operation on the second USB flash drive area or the encryption area; when the received instruction is a read/write instruction for the encryption area sent by the upper layer, executing a read/write operation on the encryption area; if the SD card is an invalid SD card, when the received instruction is a partitioning instruction, the security chip of the dongle executing a partitioning operation according to a partition information table in the partitioning instruction, storing the partition information table to a secure storage area of the security chip of the dongle, and setting the SD card to be valid. The present invention can ensure that data stored in an SD card is not prone to damage or stealing.