In　this　article,　we　study　the　time　discretization　of　the　first　order　decoupled　semi-implicit　scheme　of　the　3D　primitive　equations　of　the　ocean　in　the　case　of　the　non-slip　and　non-heat　flux　boundary　conditions　on　the　side.　The　almost　unconditional　stability　of　the　scheme　and　the　optimal　error　estitinates　of　the　time　discrete　velocity,　pressure　and　density　are　provided.　(C)　2013　Elsevier　Inc.　All　rights　reserved.