To investigate the four-phase computed tomography (CT) features of rectal neuroendocrine neoplasms (R-NENs) as they relate to different World Health Organization pathological grades.A total of 42 patients who underwent pre-operative four-phase CT for evaluation of neoplasms confirmed as different pathological grades of R-NENs by surgery were included. The CT features were retrospectively analyzed by two radiologists in consensus including the tumor location, shape, long diameter, necrosis, boundary, transmural invasion, CT attenuation values of noncontrast and different enhancement phases, intra mesenteric metastasis, lateral lymph node metastasis, and distant metastasis. The differences among R-NENs of different pathological grades were analyzed using T-test, analysis of variance, and non-parametric rank sum test.Among 42 cases (23 males, 19 females, aged 57 ± 10.48 years) of R-NENs, neuroendocrine tumors G1, G2, and G3 (NET G1, NET G2, NET G3) and neuroendocrine carcinoma (NEC) were 13, 13, 3 and 13 cases, respectively. There were statistically significant differences in tumor long diameter, shape, necrosis, boundary, transmural invasion, CT values in delayed phase, intra mesenteric metastasis, lateral lymph node metastasis, and liver metastasis of different pathological grades (P < 0.001, P = 0.014, P = 0.004, P < 0.001, P < 0.001, P = 0.038, P = 0.006, P = 0.022, and P = 0.020, respectively).Features on four-phase CT can correlate with WHO pathological grades of R-NENs; this may be helpful for preoperative diagnosis and prognosis evaluation.