Aim: In order to explain the rnechanism of vascular smooth muscle cells (SMC) proliferation, we tried to find some factors positively affecting on the junctional communication and expression of connexin 43.Methods: The method called scrape loading dyetransfer was used to test effects of nifedipine on cultured rat SMC's junctional communication. We used micro-fluorescence spectrophotometer for quantitation.On the other hand, the expression of connexin 43 in cultured SMC was determined with S-P immunohisto chemistry. The quantity of expression of connexin 43 was analysed with image computer.Results: Nifedipine promoted junctional communication and expression of connexin 43 in cultured rat SMC. Phorbol ester inhibited junctional communication and expression of connexin 43.Conclusion: The possible mechanism of inhibiting proliferatlon of SMC and preventing atherosclerosis for nifedipine could be partly through prornoting junctional communication and expression of connexin 43.