The invention discloses a security protection system based on a behavior fingerprint. The system comprises a collection module, a training module and a comparison module. The collection module is used for collecting behavior fingerprint information of a user and transmits the behavior fingerprint information to the training module. The training module models to obtain a judging threshold value of the behavior fingerprint information by employing a SVM. The comparison module receives new fingerprint information from the collection module and compares the fingerprint information with the judging threshold value, thereby identifying a user identity. According to the system, an attack behavior of an invader can be discovered in real time and can be blocked actively, the security and normal operation of a mobile terminal can be ensured, the security cost is reduced, the reservation cost of the user for a key is reduced, the risk of losing the key is reduced, and the system is operated along with the original protection system, thereby increasing a security protection measure. When the system is employed by the user, a whole process can be protected, the user does not need to remember any key, a hidden protection effect is realized, the system is taken as a second defense line for the security of the mobile terminal of the user, and the system has wide applicability.