Raman　spectra　of　crystal-octadecyl　hydrogen　maleate　(OHM),　whose　geometric　disposition　of　the　experiment　has　y　over-bar　(zx)y　y　over-bar　(zz)y,　and　y　over-bar　(xz)y,y　over-bar　(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.