When　users　use　Virtual　Reality　(VR)　in　nontraditional　postures,　such　as　while　reclining　or　lying　in　relaxed　positions,　their　views　lean　upwards　and　need　to　be　corrected,　to　make　sure　they　see　upright　contents　and　perceive　the　interactions　as　if　they　were　standing.　Such　upright　redirection　is　excepted　to　cause　visual-vestibular-proprioceptive　conflict,　affecting　users＇　internal　perceptions　(e.g.,　body　ownership,　presence,　simulator　sickness)　and　external　perceptions　(e.g.,　egocentric　space　perception)　in　VR.　Different　body　reclining　angles　may　affect　vestibular　sensitivity　and　lead　to　the　dynamic　weighting　of　multi-sensory　signals　in　the　sensory　integration.　In　the　paper,　we　investigated　the　impact　of　upright　redirection　on　users＇　perceptions,　with　users＇　physical　bodies　tilted　at　various　angles　backward　and　views　upright　redirected　accordingly.　The　results　showed　that　upright　redirection　led　to　simulator　sickness,　confused　self-awareness,　weak　upright　illusion,　and　increased　space　perception　deviations　to　various　extents　when　users　are　at　different　reclining　positions,　and　the　situations　were　the　worst　at　the　45°　conditions.　Based　on　these　results,　we　designed　some　illusion-based　and　sensory-based　methods,　that　were　shown　effective　in　reducing　the　impact　of　sensory　conflict　through　preliminary　evaluations.　©　2022　ACM.