Molecular　dynamics　simulations　based　on　reactive　empirical　bond　order　potentials　are　performed　to　investigate　the　attributes　of　the　thermally　agitated　ripples　in　single-layer　molybdenum　disulfide　(SLMoS2)　membranes,　including　the　vibrational　mode　and　the　height　fluctuation.　The　effects　of　aspect　ratio,　type　and　shape　of　boundary　conditions,　and　chirality,　on　the　attributes　of　the　ripples　are　mainly　concerned.　The　aspect　ratio　has　a　major　influence　on　the　vibrational　mode　of　the　ripples　for　rectangular　SLMoS2　membranes.　Most　of　the　effect　of　chirality　is　concentrated　on　the　height　fluctuation　for　the　slender　SLMoS2　nanoribbons　due　to　inducing　different　number　of　ripples.　The　types　of　boundary　conditions　is　shown　to　have　minor　influence　on　the　vibrational　mode　and　height　fluctuation　for　the　rectangular　SLMoS2　membranes.　Only　high-order　resonant　mode　is　thermally　agitated　in　SLMoS2　nanosheets　with　circular　boundary　conditions.　The　height　fluctuation　in　most　of　SLMoS2　membranes　increases　with　increasing　the　temperature,　which　is　consistent　with　the　elastic　theory　of　membrane.　The　work　can　be　useful　for　the　application　of　strain　engineering　in　SLMoS2　nanodevices.　©　2017　Elsevier　B.V.