In order to study the chemical constituents from the roots of Dysoxylum densiflorum and their protein tyrosine phosphatase 1B(PTP-1B) inhibitory activity.Twenty-three compounds were isolated from the D. densiflorum applying various chromatographic techniques.Their structures were elucidated and identified as 5(10),13E-halimadiene-3α,15-diol（1）,(-)-agbanindiol A（2）,polylauioid H（3）,2-oxopopulifolic acid（4）,dysoxydenone C（5）,2-oxo-ent-cleroda-3,13Z-dien-15-oic acid（6）,nakamurol B（7）,methyl (13E)-2-oxoneocleroda-3,13-dien-15-oate（8）,15-acetoxy-ent-3,13E-clerodadien-2-one（9）,(3α,4β,13E)-neoclerod-13-ene-3,4,15-triol（10）,5(10),14-halimadiene-3α,13ξ-diol（11）,dysokusone A（12）,14,15-dinorclerod-3-ene-2,13-dione(13）,3,4-epoxyclerodan-13E-en-15-oic acid（14）,dysokusone G（15）,15-acetyloxyl-3α,4β-dihydroxy-neoclerod-13Z-ene（16）,［1α(E),2β,4aβ,8aα］-5-(decahydro-4a-hydroy-1,2,5,5-tetra-methyl-1-naphthalenyl)-3-methl-2-penten-1-ol（17）,kolavenol（18）,(13E)-2-oxoneocleroda-3,13-dien-15-ol（19）,2β-hydroxykolavenol（20）,ent-3β,4β-epoxyclerod-13E-en-15-ol（21）,2-oxodihydrokolavenol acetate（22）,(3α,4β,13E)-4-ethoxyneoclerod-13-ene-3,15-diol（23）.Compounds 2,4,6-9,11,13,14,17-20,22-23 are obtained from Dysoxylum for the first time.Compounds 3,12,16 and 21 had PTP-1B inhibitory activity with the IC₅₀ values were 31.25±0.64,0.30±0.56,0.64±0.51 and 78.50±0.59 μmol/L,respectively.