During a new antibiotic screening program, albothricin (1), a streptothricin-group antibiotic, was isolated from the culture broth of strain SIPI-2985—a rare actinomycete (cell wall containing meso-diaminopimeric acid) isolated from Hainan island soil. This paper reports its isolation, structural elucidation, and biological activities. The producing strain was fermented, and albothricin was purified using chromatographic methods. Structural analysis (13C NMR, FAB-HRMS, acid hydrolysis, 2D-COSY, 13C-1H shift correlation, 1H spin decoupling, and NOE experiments) determined its molecular formula C20H36N8O7 and structure featuring a 4-deoxystreptolidine moiety (a first for streptothricins). Antimicrobial testing showed activity against Gram-positive (e.g., Staphylococcus aureus, MIC 1.56-3.13 µg/ml) and Gram-negative bacteria (e.g., Escherichia coli, MIC 3.13-6.25 µg/ml). No acute toxicity was observed in ICR mice at 200 mg/kg intravenous administration, but injection site necrosis occurred. Albothricin is the first streptothricin with a 4-deoxystreptolidine moiety and the first streptothricin produced by a rare actinomycete.