The invention discloses a data processing method. The data processing method comprises the steps: when a terminal device is used to login a cloud account number, acquiring the identity information of an SIM card of the terminal device; when the login password of the cloud account number is correct, verifying whether the identity information bound with the cloud account number is matched with the identity information of the SIM card; when the identity information bound with the cloud account number is not matched with the identity information of the SIM card, locking the terminal device, and backup the data in the terminal device to a cloud server; and when data backup of the terminal device is completed, deleting the data in the terminal device from the terminal device, wherein the data in the terminal device includes the cloud account number and the login password, of the cloud account number, recorded by the terminal device. The embodiment of the invention also provides a data processing device. The data processing method and device can improve the safety of cloud account numbers.