Abstract: Objective 　To study whether PP2 42Amino252(42Chloro2Phenyl)272(t2Butyl) Pyrazolo 3, 42d Pyrimidine could change the expression of src kinase and E2cadherin protein, and detect the proliferation and invasion of breast cancer cell. Methods 　Af ter t reating MDA2MB2231 with PP2, western blot was performed to determine the expression of src and E2cadherin ; The proliferation was been tested by MTT assay ; Boyden chamber assay was used to examine the effect of the invasion of MDA2MB2231 cell. Results Western blot show if the dosage of PP2 increase, the expression of src is down2regulated and E2cadherin is up2regulated. MTT assay show that the proliferation of MDA2MB2231 have association with PP2 dos2 age ( P < 0. 05 ) . Boyden chamber assay show that the invasion is downregulated when the dosage of PP2 is enhanced ( P < 0. 05 ) . Conclusion 　PP2 can st rongly inhibit src and enhance the expression of the downst ream protein of E2cadherin. The proliferation and invasion of MDA-MB2231 cells is also inhibited by PP2.