Based　on　the　Keldysh　non-equilibrium　Green　function　method,　the　spin-polarized　transport　properties　in　a　coupled-double-quantum-dot　(CDQD)　system　with　ferromagnetic　electrodes　(FM-CDQD-FM)　are　investigated.　It　is　clearly　seen　that,　in　contrast　to　the　steplike　or　basin-like　behaviors　of　the　spin　(electrical)　current　in　the　FM-QD-FM　system　(Mu　et　al　2006　Phys.　Rev.　B　73　054414),　the　resonant　tunneling　determines　the　main　features　of　the　spin　(electrical)　current　in　the　FM-CDQD-FM　system.　It　must　originate　from　the　coupling　effect　between　two　dots,　which　destroys　the　Coulomb　blockade　(CB)　effect　and　makes　electron　spin　transport　mainly　depend　on　the　cotunneling.　Furthermore,　it　is　also　found　that　spin-polarized　transport　in　the　system　is　evidently　modulated　by　the　coupling　strength　between　two　dots,　which　results　from　the　non-equilibrium　spin　accumulation　and　the　spin　precession　for　the　presence　of　ferromagnetic　electrodes.