In　this　paper,　by　using　the　cyclostationary　properties　of　speech　signal,　a　voice　activity　detection　(VAD)　algorithm　based　on　cyclic　cumulant　is　proposed.　The　proposed　scheme　employs　the　thirdorder　cyclic　cumulant　of　the　LPC　residual　of　a　speech　signal.　Analytical　expressions　for　the　third-order　cyclic　cumulant　of　the　LPC　residual　of　short-term　speech　are　derived　assuming　a　sinusoidal　model.　Matrix　pencil　method　(MP)　are　adopted　to　estimate　the　frequencies　of　harmonic　signal　contained　in　LPC　residual　of　speech　signal,　which　are　used　as　the　cyclic　frequencies　of　cyclic　cumulant.　Then　the　third-order　cyclic　cumulant　is　defined　and　used　to　construct　the　VAD　detection　variation.　The　test　results　show　that　the　proposed　algorithm　gives　better　results　than　G.729B　VAD.　©　2008　IEEE.