Parkinson's disease (PD) is associated with mitochondrial dysfunction, oxidative stress, and activation of the apoptotic cascade. In the study, we investigated the effects of salvianolic acid B (Sal B) on 1-methyl-4-phenylpyridinium (MPP(+))-treated SH-SY5Y cells, a classic in vitro model for PD. We found Sal B inhibited the loss of cell viability by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The underlying mechanisms of Sal B action were further studied. Treatment of SH-SY5Y cells with MPP(+) caused a loss of cell viability and mitochondrial membrane potential, condensation of nuclei, elevation in the level of reactive oxygen species (which was associated with cytochrome c release), an increase in the Bax/Bcl-2 mRNA ratio, and activation of caspase-3. Sal B ameliorated the MPP(+)-altered phenotypes. These results indicate that the Sal B protected SH-SY5Y cells against MPP(+)-induced apoptosis by relieving oxidative stress and modulating the apoptotic process. Our findings suggest that salvianolic acid B may be a promising agent to prevent PD.