Digital media profoundly shapes the cognitive structures and psychological states of young people, and the high penetration of short videos has triggered the systematic dissipation of their confidence in development. How to understand and effectively intervene in the impact of short videos on young people’s confidence has become a key issue in current theoretical research and practical responses.Based on dissipative structure theory, this study regards young people’s confidence as a system characterized by openness, nonlinearity, distance from equilibrium, and fluctuations. It uses data from the China Family Panel Studies (CFPS) 2014—2022 and the difference-in-differences method to analyze the impact of short videos on young people’s confi〖JP3〗dence in development.Empirical findings show that the use of short videos significantly weakens young people’s〖JP〗 confidence in development, and this effect exhibits high consistency across groups with different demographic characteristics. Mechanistic analysis further reveals that short videos indirectly affect confidence through two pathways: First, short videos algorithmically strengthen the social comparison effect, weaken young people’s identification with their own class identity, shake the cognitive foundation of their social status, and thereby reduce their confidence in development. Second, the information cocoon of short videos reduces young people’s perception of social risks, trapping them in a subjective pseudo-equilibrium state, weakening their momentum to cope with real-world problems, and indirectly impacting the confidence system.Therefore, suggestions are put forward in four aspects: optimizing information openness to construct a positive entropy input mechanism; promoting dynamic non-equilibrium to enhance young people’s media literacy; utilizing the fluctuation effect to inspire a leap in young people’s confidence; and strengthening nonlinear regulation to establish a multi-level collaborative intervention system.The study, theoretically, expands the nonlinear dynamic pathways through which short videos affect young people’s confidence; methodologically, breaks through the linear causal framework and reveals the dual mediating pathways of class identity and risk perception; and practically, provides the logic of entropy flow regulation and intervention as well as empirical support for enhancing young people’s confidence.