Four new stilbene derivatives, hypargystilbenes B-E (1-4), together with seven known compounds (5-11), were isolated from the stems of Artocarpus nanchuanensis S.S. Chang. Their structures were elucidated on the basis of spectral data. Hypargystilbene B, hypargystilbene D, and hypargystilbene E exhibited protein tyrosine phosphatase 1B inhibitory effects with corresponding IC50 values of 3.23, 37.31, and 2.53nM.