Certain　almost　periodic　forced　perturbed　systems　with　piecewise　argument　are　considered　in　this　paper.　By　using　the　contraction　mapping　principle　and　some　new　analysis　technique,　some　sufficient　conditions　are　obtained　for　the　existence　and　uniqueness　of　almost　periodic　solution　of　these　systems.　Furthermore,　we　study　the　harmonic　and　subharmonic　solutions　of　these　systems.　The　obtained　results　generalize　the　previous　known　results　such　as　[A.M.　Fink,　Almost　Periodic　Differential　Equation,　Lecture　Notes　in　Math.,　vol.　377,　Springer-Verlag,　Berlin,　1974;　C.Y.　He,　Almost　Periodic　Differential　Equations,　Higher　Education　Press,　Beijing,　1992　(in　Chinese);　Z.S.　Lin,　The　existence　of　almost　periodic　solution　of　linear　system,　Acta　Math.　Sinica　22　(5)　(1979)　515-528　(in　Chinese);　C.Y.　He,　Existence　of　almost　periodic　solutions　of　perturbation　systems,　Ann.　Differential　Equations　9　(2)　(1992)　173-181;　Y.H.　Xia,　M.　Lin,　J.　Cao,　The　existence　of　almost　periodic　solutions　of　certain　perturbation　system,　J.　Math.　Anal.　Appl.　310　(1)　(2005)　81-96].　Finally,　a　tangible　example　and　its　numeric　simulations　show　the　feasibility　of　our　results,　the　comparison　between　non-perturbed　system　and　perturbed　system,　the　relation　between　systems　with　and　without　piecewise　argument.　©　2006　Elsevier　Inc.　All　rights　reserved.