This paper focuses on the issue of dynamic event‐triggered (DET) asynchronous security load frequency control (LFC) for uncertain semi‐Markov jump interconnected multi‐area power systems (IMAPSs). Initially, the semi‐Markov process which in the presence of partially unknown transition rates (TRs) is exactly introduced to model the switching behaviors of the IMAPSs. Subsequently, the DET mechanism is scheduled to alleviate the transmission frequency and guarantee the desired control performance. Furthermore, the probabilistic deception attacks are taken into consideration, which is much more apt for the practical engineering background. Additionally, a hidden Markov model (HMM) is borrowed to depict the modes asynchronous phenomenon between the security controller and the semi‐Markov jump IMAPSs. Afterwards, on the basis of Lyapunov‐Krasovskii functional method and stochastic analysis technique, sufficient conditions with two cases are derived in the form of linear matrix inequalities (LMIs) to guarantee the stochastic stability with an performance of the semi‐Markov jump IMAPSs. Ultimately, a numerical example is exhibited to verify the solvability and practicability of the proposed control strategy.