In　organic　semiconductor　spintronic　devices,　the　up-spin　and　down-spin　polarons　have　different　density　once　spin　injection　happens　from　ferromagnetic　electrodes　into　organic　semiconductors.　For　the　different　spin　density　of　two　spin　channels　could　induce　different　conductivity,　the　different　conductivity　between　the　up-spin　and　down-spin　polarons　directly　dominates　the　spin　polarization.　Here　the　effect　of　spin-dependent　conductivity　on　the　spin　polarization　is　extensively　studied　applying　the　spin　drift-diffusion　equation　on　the　ferromagnetic　(FM)/organic　(OSE)　structure.　It　is　found　that　the　spin　dependence　of　the　electrical　conductivity　is　induced　by　the　spin　injection　and　closely　related　to　the　induced　spin　density　(or　spin　accumulation)　mu(down　arrow)　-　mu(up　arrow).　The　calculations　show　that　the　electrical　conductivity　induced　by　up-spin　polarons　(down-spin　polarons)　is　position-dependent　in　the　OSE　just　as　the　spin　accumulation.　And　the　match　level　of　conductivities　sigma(0)/sigma(f)　can　affect　the　spin-dependent　conductivity　at　the　interface　of　the　FM/OSE　to　a　great　extent.　In　addition,　it　is　found　that　the　electric-field　can　affect　the　current　spin　polarization　alpha(x)　in　the　FMI/OSE　system　in　the　low-voltage　regime　(eV　＜＜　k(B)T).　(C)　2009　Elsevier　B.V.　All　rights　reserved.