This paper concentrates on attack-resilient event-triggered formation control of multi-agent systems (MASs) under periodic Denial-of-Service (DoS) attacks, which involves a new technique based on complex Laplacian. Firstly, periodic DoS attacks are modeled as Bernoulli distribution where the considered plant is viewed as a stochastic system. Then, a novel attack-resilient event-triggered mechanism (ARETM) is put forward to address formation shape problems of the system. ARETM not only restrains periodic DoS attacks effectively, but also saves network resources greatly and excludes Zeno behavior naturally. Moreover, the system stability is analyzed by using a generalized Nyquist stability criterion, in which a distinctive homotopy Newton iterative algorithm is introduced. Finally, numerical simulation cases are presented to explain the effectiveness of the designed method.