Objective In this study, the ¹¹¹In-labeled bleomycin complex (¹¹¹ In-BLMC) was used as a Single-Photon Emission Computed Tomography (SPECT)-tracking agent to differentiate the high-grade and low-grade gliomas innude mice. Methods Thirty-four nude mice with gliomas,induding 22 high-grade and 12 low-grade gliomas,were used inthis study.SPECT was performed 10 min after the injection of ¹¹¹In-BLMC to the mice. Semi-quantitative analysis by imagingwas performed at the early and delayed phases. The ¹¹¹In-BLMC early- and delayed-phase uptake indexes and retentionindexes were obtained. Results All SPECTs were positive for ¹¹¹In-BLMC markers. In the high-grade glioma group, theearly- and delayed-phase ¹¹¹In-BLMC uptake indexes and retention indexes were (3. 47± 1. 66) and (5. 193± 1. 49),respectively. In the low-grade glioma group, the mid-, early-, and delayed-phase ¹¹¹In-BLMC uptake indexes and retentionindexes were (1. 59±1. 68) and (2. 99±1. 36), respectively, both differences were statistically significant ( P < 0. 01).When the intake index was < 1. 898, the sensitivity of diagnosis of low-grade glioma was 66. 67% and the specificity was85. 71% ( P < 0. 01); when the retention index was < 3. 155, the sensitivity of diagnosis of low-grade glioma was58. 33%,and the specificity was 63. 66% ( P < 0. 01). Conclusions ¹¹¹In-BLMC-labeled glioma SPECT can provide somehelp for preoperative tumor grading. The uptake index and the retention index enable a relatively accurate judgment of the degree of malignancy of gliomas.