The interaction between VIP and nucleotide was tested with advanced photo-affinity technique.It was found that VIP can bind radiolabled GTP specifically and this binding could be competitively inhibited by cold GTP(unlabled GTP).The experiment indicated that not only GTP could inhibit the binding between VIP and hot GTP, but also all other nucleoside triphophates such as ATP,TTP,UTP could competitively inhibit this binding,although their inhibitions were a little weaker than GTP.It means VIP binding nucleoside triphbsphate was a typical reversible binding reaction. It was found also that GDP, GMP at low concentration did not inhibit VIP binding hot GTP but enhanced the binding. Connecting with other researchers' results of GTP influencing on VIP-receptor interaction, it was considered that VIP could reversibly bind one of nucleoside triphosphates and this binding was modulated by the ratio of different nucleotides in reaction system. Through this binding, the interaction of VIP and it's receptor was regulated.