Objective:To construct rat Pik3cb(phosphatidylinositol 3-kinase,catalytic,beta polypeptide) shRNA eukaryon plasmid express vector,and test its downregulating effect on Pik3cb mRNA expression for the application of RNA interference in restraining vein graft restenosis. Methods:Two shRNA of rat Pik3cb were design and synthesize according to the sequence of Pik3cb in the Genbank,annealed to form double strands and then cloned into pGenesil-1,and then the sequences were examed. After shRNAs were transfected into rat thoracic VSMC through METAFECTENETM,the transfection rate was identified by EGFP. pAkt-473 protein expression was detected by Western blot,and cell apoptosis were obtained through flow-cytometry. Results:The two sequences of synthesized shRNA named pU6-Pik3cb-shRNA-1 and pU6-Pik3cb-shRNA-2 were exactly the same with the design. The 48 h and 72 h transfection rate were 15.7% and 10.1%,respectively. The pAkt-473 protein expression significantly reduced,while the apoptosis cells were more significantly increased in the shRNA groups than the control groups(P < 0.05). The scramble shRNA did not interfere with the VSMC proliferation. Conclusion:Rat Pik3cb shRNA eukaryon express plasmid vectors were constructed successfully and effectively inhibited the proliferation of rat smooth mouse cells.