The ointment of plastrum testudinis was extracted using petroleum ether,ether and dichloromethane sequentially and the extracts were methyl,esteri,fled. The effects on the proliferation of bone marrow mesenchymal stem cells (bMMSCs) were examined by MTT[3,(4,5,dimethylthiazol,2,yl),2,5,diphenyl tetrazolium bromide] assay and flow cytometry analysis. The volatile components of the samples were studied by gas chromatography,mass spectrometry (GC,MS) and high performance liquid chromatography (HPLC). The results show that the methyl,esterified parts can promote the proliferation of stem cells and they all contain palmitic acid methyl ester. Palmitic acid methyl ester can promote proliferation when the concentration was 0.15 μg/μL. It may be concluded that the palmitic acid methyl ester is important for the methyl,esterified parts that have effects on proliferation.