<p>This paper addresses an event-triggered predefined-time bipartite consensus control strategy for second-order multi-agent systems with external disturbances under signed networks. First, based on the backstepping method and a designed event-triggered mechanism, an event-triggered control strategy is developed to achieve predefined-time bipartite consensus in signed graphs, where the upper bound of convergence time can be preset via a controller parameter and remains independent of the system's initial states. Second, the study is extended to multi-agent systems with switching topologies and signed networks, for which a predefined-time event-triggered bipartite consensus controller is designed. Then, by employing algebraic graph theory and Lyapunov stability theory, it is rigorously proved that the proposed control strategy guarantees predefined-time stability of the system while excluding Zeno behavior. Finally, comparative simulation experiments demonstrate the effectiveness of the proposed control strategy. The results show that the strategy maintains predefined-time stability and bipartite consensus under different initial conditions. This research provides a novel solution for consensus control of multi-agent systems in complex network environments, offering significant theoretical importance and practical value for enhancing robustness and response speed.</p>