| Objective To identify the active secondary metabolites of the coral fungus Aspergillus sp. OUCMDZ-3658 from XiSha Islands. Methods The isolations and purifications of compounds were performed by means of solvent extraction, column chromatography over silica gel, Sephadex LH-20 and HPLC. And their structures were elucidated through the analysis of MS, NMR, [α]D and CD. The bioactivities were assayed by MTT, paper diffusion and the α-glucosidase inhibition methods. Results From the cultures of Aspergillus sp. OUCMDZ-3658, we isolated thirteen alkaloids (1-13) and a fusidane-type triterpenoid (14). Their structures were identified as fumiquinazolines A (1) and C (2), fumiquinazolines D (3) and F (4), chaetominine (5), pseurotins A1 (6) and A2 (7), fumitremorgin C (8), cyclouyprostatin A (9), 12β-hydroxy-13α-methoxyverruculogen TR-2 (10), 9H-pyrido[3,4-b]indole-3-carboxylic acid (11), (–)-cyclopenol (12), pyripyropene A (13) and helvolic acid (14), respectively. Compounds 8 and 9 showed weak antibacterial activity against Enterobacter aerogenes while compound 10 showed weak antifungal activity against Candida albican with MIC values of 33.0, 30.4 and 56.4 μmol/L, respectively. Compounds 3 and 4 displayed comparable α-glucosidase inhibition to acarbose (positive control) with the IC50 values of 0.87, 1.14 and 1.11 mmol/L, respectively. Conclusion This paper reported the α-glucosidase inhibition of fumiquinazolines D (3) and F (4) for the first time and thus afforded the new structure-type for screening of α-glucosidase inhibitors.