Allicin （Diallyl thiosulfinate）， has a broad-spectrum bacteriostatic， tumor-inhibiting and antioxidant activity. However， allicin is extremely unstable. and easily degraded into various organic sulfur compounds， which greatly reduces its activity. Studies have shown that the disulfide bond conjugate formed by allicin and whey protein isolate could significantly enhance the stability of allicin. In this paper， the in vitro simulated digestion characteristics of the allicin extract and disulfide conjugates were studied. Results showed that after simulated digestion of allicin and whey protein isolate conjugates， the sulfur compound composition were the same as the digestion product of allicin extract. The results indicated that the combination rate of allicin to protein would not affect the release of allicin active components. 3-vinyl-1， 2-dithiocyclohexe-4-ene was released mainly during simulated gastric digestion， while diallyl disulfide was released mainly during simulated intestinal digestion. Combined with allicin did not affect the degree of hydrolysis of whey isolate during simulated gastrointestinal digestion. Compared with protein， the content of small molecular weight components in the digested product of the conjugates increased， indicating that the conjugates were more easily absorbed and utilized than the protein.