Raman　spectra　of　crystal-octadecyl　hydrogen　maleate　(OHM),　whose　geometric　disposition　of　the　experiment　has　ȳ(zx)y　ȳ(zz)y,　and　ȳ(xz)y,ȳ(xx)y　respectively,　have　been　recorded　and　analyzed　with　the　purpose　of　understanding　the　structure　of　OHM　crystal.　It　shows　that　some　of　the　Roman-active　modes　of　alkyl　chain　appear　polarization.　The　analysis　for　crystal　structure　indicates　that　the　molecular　of　OHM　arrange　in　layers　along　[100]　and　[001]　by　the　mode　of　dimers,　and　the　molecular　layers　of　chain　pile　up　along　[010].　The　other　groups　of　OHM　corresponding　Raman　vibration　peaks　have　been　analysed　as　well.