Detailed phytochemical investigation from the root bark of Morus alba resulted in the isolation of eleven new compounds, including seven 2-arylbenzofuran derivatives (morusalfurans A–G), three flavonoids (morusalnols A–C), and one geranylated stilbene (morusibene A), as well as 22 known compounds. The structures of the identified compounds were elucidated based on a comprehensive analysis of spectroscopic data and Mosher’s method. Compounds 2, 3, 6–8, 11, 23, 24, and 29 showed potent inhibition of PL in comparison with the positive control treatment (orlistat, IC50=0.012μM), with IC50 values ranging from 0.09 to 0.92μM.