To identify the key causal factors of team error in the main control room (MCR) of nuclear power plants (NPPs), the behavioral modes and performance shaping factors (PSFs) of team error are derived by analyzing the human event reports of Chinese NPPs from 2017 to 2021. Next, a team error causal network, containing error and PSF, is established, and the network’s topological features are analyzed. Finally, three node attack strategies are used to evaluate the robustness and vulnerability of the network, for determining the key causal factors of team error. The results show that the team error causal network exhibits certain robustness in the face of random attack and vulnerability in the face of deliberate attack. Compared with the DB strategy, the DD strategy can effectively destroy the network’s connectivity and prevent team error. Hence nodes with a high degree of centrality are the key modes and key PSFs of team error, i.e. the key modes of team error are negligence, failure to assess, failure to make a decision, violated operation, and failure to perceive information. The key PSFs of team error are team quality and ability, organizational management, team psychological states, team cooperation, and procedure. The results help to clarify the complex causal relationship in team error and provide a theoretical basis for the prevention and control of team error.