In order to explore the real effect of art mental health therapy, this paper proposes a feature selection algorithm based on genetic algorithm. The algorithm takes college students as the research object and discusses the effect of psychotherapy on college students through painting art therapy. The results showed that there were extremely significant differences in EPQ extraversion factors among the people treated with the educational intervention of art psychology course ( P < 0.01 ), and there was no significant change in other factors ( P > 0.05 ). There was no significant change in total depression score and depression index ( P > 0.05 ). There were significant differences in social avoidance factors and social anxiety ( P < 0.05 ), and there were relatively significant differences in the total score of sadness ( P < 0.01 ). It is concluded that the use of artistic elements can effectively help people express themselves and express their psychological emotions, which has a certain effect in mental health treatment.