Recently, individual extreme violent crimes have experienced a resurgence, posing greater challenges to social prevention and control. Individual extreme violent criminals tend to exhibit traits of mental disorders dominated by “paranoia, impulsivity, and weak social adaptability”, which reveals the possibility that they suffer from mental illnesses. Through relevant theoretical interpretations and illustrations of cases, this paper extracted and summarized the behavioral characteristics, psychological motives, and behavioral expressions of individual extreme violent criminals suffering from schizophrenia, related personality disorders, and neuroses, which were further combined with the development and application of smart public security, in the hope of proposing comprehensive countermeasures psychologically targeted at individual extreme violent criminals with traits of mental disorders.