The invention discloses an oil displacement effect detection method and device. The oil displacement effect detection method comprises carrying out dehydrogenation treatment on a rock core to be detected so that a dehydrogenized rock core is obtained and detecting oil displacement effects based on the dehydrogenized rock core. The rock core to be detected is subjected to dehydrogenation treatment so that oil displacement result detection influence caused by hydrogen in minerals of the rock core to be detected is avoided, related technology problems of low accuracy of oil displacement effect analysis based on a magnetic resonance imaging technology are solved and oil displacement effect analysis accuracy is improved.