The psychological aspects of finger biting are mainly the following: first, tension, many people will be nervous when accompanied by behavioral performance and increased performance of action, such as expressions of special tension, constantly walking around, always fidgeting, while rubbing their hands, picking their hands, pinching their corners, etc., but also some people will appear to bite their fingers when nervous, anxious behavior. Second, it may be a bad habit, especially from childhood, may have the habit of biting fingers since childhood, and even bite their fingers bald, bite bleeding, etc.. Third, it may also be obsessive-compulsive disorder (OCD), which has a special form of expression based on itself or concern for its own performance, such as repeatedly focusing on whether their appearance has been deformed, repeatedly pulling hair, picking hands, biting fingers, etc. These are also behavioral manifestations of OCD.