The article is devoted to improving psychological support for volunteering in extreme conditions. The emphasis is placed on the establishment of predictors of personal choice of participation in volunteerism, the development of an integrative model and diagnostic tools for assessing readiness for participating activities. The subject of the study is a model of personal choice of participation in extreme volunteerism. The aim is to substantiate an integrative model of personal choice of participation in extreme volunteerism, to develop an appropriate diagnostic methodology based on it. The methodological basis is based on axiological, holistic, activity-based and subjective approaches. Semantic analysis of diagnostic constructs, as well as expert assessment and psychological testing were used (questionnaire «Scale of dispositional egoism» (K. Muzdybaev); questionnaire «Motivation for help» (S.K. Nartova-Bochaver); questionnaire of value orientations (adaptation of M. Rokich's methodology); indicative questionnaire «Personality orientation» (V. Smekal, M. Kucera adaptation by N.M. Peisakhov); questionnaire on motivation of volunteer activity (K.V. Gil); methodology for diagnosing achievement motivation (A. Mehrabian); methods of diagnosing personal maturity (V.A. Ruzhenkov); test of resilience (S. Muddy, adaptation by D.A. Leontiev, E.I. Rasskazova); questionnaire «Coping behavior» (R. Lazurus, S. Folkman, adaptation by S. Hobfall); value questionnaire (Sh. Schwartz); original author's methods – a questionnaire for assessing the propensity to extreme volunteering, an assessment of manifestations of professional personality deformation, a questionnaire for evaluating the choice of participation in extreme volunteerism). The sample size is 218 people. Applied: descriptive statistics, factor analysis, meta-analysis of data. According to the results of the study, the 16 factor structure of the choice of complicity is justified, which includes: «Prosocial value orientations», «Ideality», «Integrity of worldview», «Voluntary sense orientation», «Motivation», «Interest in volunteerism», «Propensity to extreme activity», «Dedication», «Critical thinking», «Extreme perceptual congruence», «Emotional stenicity», «Self-control», «Activity in extreme conditions», «Extreme vitality», «Self-organization», «Reliability». The novelty lies in the development of an integrative model and a questionnaire for evaluating the choice of participation in volunteerism. The results can be applied by psychologists of law enforcement agencies and volunteer organizations in conducting psychological selection and training of volunteers.