Objective To explore the efficacy and safety of granulocyte and monocyte apheresis(GMA) in the patients of moderate to severe inflammatory bowel disease(IBD). Methods Thirty-eight patients of moderate to severe IBD received GMA treatment at our hospital from May 2013 to September 2021 were enrolled, which included 28 cases of ulcerative colitis(UC) and 10 cases of Crohn disease(CD); and the data were analyzed retrospectively. The indexes including patients’ disease clinical activity scores [Mayo score, CD activity index(CDAI) score], endoscopic activity scores [UC endoscopic index of severity (UCEIS) score, Mayo endoscopic (MES) score, Baron score, CD endoscopic index of severity(CDEIS) score], changes in laboratory tests, and adverse events were compared before and 2 weeks after GMA treatment. Results After GMA treatment, the overall clinical response rate in 38 patients was 79% and remission rate was 42%; in which, the efficacy rate in 28 UC patients was 82%(n=23), and 10(36%) patients were in remission; the efficacy rate in 10 CD patients was 70% (n=7), and 6 (60%) cases were in remission. In UC patients, GMA significantly decreased Mayo score, UCEIS score, MES and Baron score. In CD patients, GMA significantly decreased CDAI score and CDEIS score(P<0.05). In all patients with IBD, GMA significantly increased the level of hemoglobin (Hb) and albumin (Alb), and reduced C-reactive protein (CRP) levels and defecate frequency (P<0.05). There was no significant difference in white blood cell (WBC), neutrophil (N)%, lymphocyte(L)%, monocyte (M)%, platelet (PLT) and erythrocyte sedimentation rate(ESR) level before and after treatment. The GMA-related severe adverse events were not observed. Conclusions GMA was effective and highly safe for the patients of moderate to severe IBD, while further randomized controlled trials in larger samples still need to be done as considering small case number in our research.