The　steam　coal　supply　chain　has　the　problem　that　the　member’s　inventory　level　cannot　change　with　the　market　demand.　The　main　reason　is　that　market　demand　information　has　not　been　shared　in　the　supply　chain　members.　This　paper　considers　the　steam　coal　supply　chain　which　consists　of　one　coal　manufacturer　and　one　fire　power　plant,　with　the　assumption　that　the　steam　coal　demand　follows　a　seasonal　autoregressive　moving　average　process,　including　marketing　actions　that　cannot　be　deduced　form　the　other　parameters　of　the　demand　process.　We　compare　the　optimal　inventory　level　of　the　steam　coal　manufacturer　and　the　power　plant　in　two　scenarios　and　analyses　the　reasons　that　influence　the　value　of　the　information　sharing　in　the　steam　coal　supply　chain.　It　demonstrates　that　the　seasonal　effect　and　lead-time　have　an　important　impact　on　optimal　inventory　policy.　This　result　provides　managers　of　steam　coal　manufacturers　and　power　plant　with　insights　to　establish　strategic　partnership　to　promote　the　performance　of　the　whole　supply　chain.　©　2016　SERSC.