Abstract: A login mechanism for an operating system, including: a computer device, loaded with a computer operating system; and a mobile device, capable of sending a login password for the computer operating system, and capable of authenticating a human biometric feature. In the login mechanism of the present invention, the login password for the computer operating system is stored on the mobile device. When a user logs in to the computer operating system, the mobile device authenticates a biometric feature. After authentication succeeds, the mobile device transfers the login password to the computer device, so as to log in to the computer operating system. A user does not need to enter a login password, and two-factor authentication including login password authentication and biometric feature authentication is used to protect the security of login to the computer operating system.