Disclosed are a method and system for unlocking a mobile terminal by playing an imitation guitar. The method comprises: creating an unlocking password, the password ciphertext of the unlocking password comprising numerical value-pair sequences composed of string numbers and tone quality numbers, and the tone quality numbers mapping with string information; configuring an unlocking interface of a mobile terminal into a playing interface of an imitation guitar; acquiring the numerical value-pair sequence composed of the string numbers and tone quality numbers of strings plucked during playing on the playing interface located at the unlocking interface; carrying out digital processing on the acquired numerical value-pair sequence composed of the string numbers and tone quality numbers, then converting a result into playing ciphertext, and comparing the playing ciphertext with the stored password ciphertext of the unlocking password; and unlocking the mobile terminal while the comparison proves that the playing ciphertext matches the password ciphertext of the unlocking password. The present invention can unlock a screen by playing an imitation guitar, thereby giving brand-new visual and auditory experience to people, increasing the user unlocking interestingness and improving user experience.