[目的/意义]频发的隐私泄露事件与日益复杂的隐私控制策略加剧了用户隐私疲劳，探究社交媒体用户隐私疲劳形成机制，能够为用户认知负荷纾解、隐私焦虑情绪调试和隐私保护有效策略制定等提供理论参考。[方法/过程]融合认知负荷、认知偏差与CAC理论，构建社交媒体用户隐私疲劳形成机制模型，使用偏最小二乘结构方程模型和模糊集定性比较分析方法进行实证检验与组态分析。[结果/结论]认知因素方面，过度自信正向影响乐观偏见，信息过载、社交过载与系统功能过载均正向影响情绪衰竭，且系统功能过载对消极怠慢也具有正向影响；情绪因素方面，情绪衰竭、消极怠慢与乐观偏见均正向影响用户隐私疲劳，且乐观偏见不仅对情绪衰竭与消极怠慢具有正向影响，还在二者的中介作用下正向影响隐私疲劳；组态效果方面，信息过载型和社交过载型两种前因构型会触发用户隐私疲劳。此外，人口统计学等控制变量对社交媒体用户隐私疲劳的影响未表现出显著性差异。

[Purpose/significance] Frequent privacy leakage incidents and increasingly complex privacy control strate⁃gies have exacerbated user privacy fatigue, and exploring the formation mechanism of social media users' privacy fa⁃tigue can provide a theoretical reference for user cognitive load relief, privacy anxiety debugging and effective privacy protection strategy formulation. [Method/process] Combining cognitive load, cognitive bias and CAC theory, the forma⁃tion mechanism model of privacy fatigue of social media users was constructed, and the partial least squares structural equation model and fuzzy set qualitative comparative analysis method were used for empirical test and configuration analysis. [Result/conclusion] In terms of cognitive factors, overconfidence positively affects optimism bias, informa⁃tion overload, social overload and system function overload all positively affect emotional exhaustion, and system func⁃tion overload also has a positive impact on negative neglect. In terms of emotional factors, emotional exhaustion, nega⁃tive neglect and optimistic bias all positively affect user privacy fatigue, and optimistic bias not only has a positive im⁃pact on emotional exhaustion and negative neglect, but also positively affects privacy fatigue under the mediating effect of the two. In terms of configuration effect, the two antecedent configurations of information overload and social over⁃load will trigger user privacy fatigue. In addition, there was no significant difference in the effect of control variables such as demographics on social media users' privacy fatigue.