Periodic　event-triggered　control　(PETC)　can　save　network　bandwidth　and　sensor　energy　at　the　same　time;　therefore,　it　is　a　promising　approach　for　applications,　especially　large　scale　plants,　such　as　smart　water　distribution　systems.　This　work　extend　PETC　by　considering　denial　of　service　(DoS)　attacks.　For　the　PETC,　a　dynamic　variable　is　introduced　with　a　switched　strategy.　Different　from　other　dynamic　variables,　our　variable　keeps　store　energy　when　there　is　no　attacks　and　only　release　energy　when　attacks　happen.　Thus,　the　inter-event　intervals　when　attacks　happen　can　be　prolonged　while　guarantees　the　same　stability　and　performance.　If　the　variable　equals　to　0　before　the　ending　of　the　attacks,　then　characteristic　of　the　attack　duration　is　analyzed　to　guarantee　a　slower　Lyapunov　convergence　rate.　The　presented　approach　is　verified　via　a　numerical　example　from　smart　water　distribution　systems.