Abstract: The application of vaccines may effectively improve their resistances against various common diseases in aquaculture，thus decrease the possibility of the incidence of diseases and infections，reduce the use of chemical drugs，eliminate the environmental pollution，and even decrease economic losses from environmental governances. Vaccination by injection is time-consuming and easily causes injuries to fishes. Vaccination by immersion needs high dosages and thus easily results in strong stress reaction. The oral vaccine can be applied to any variety and size of fish，thus may avoid the problems by injection or immersion，and it is an ideal immune approach. Among the present oral vaccines，the adjuvants like polymeric microspheres and biofilm used to prevent the antigens in vaccine from the effects of all digestive enzymes are widely applied；however，the cost is quite high in field application. Biological carrier can be a genetic engineering vaccine with antigens delivery work by non-pathogenic microorganisms，such as bacteria. These biological carrier vaccines are actually in low costs for application and induce a solid immunization effect，however，the cycle of safety evaluation is long and there is difficulty in large-scale production. This paper reviews the status and key technologies of different forms and formulations of main oral vaccines. Also the paper prospects that the study on aquatic animal oral vaccines should focus on vaccine safety and applicability in the future research work，and developing oral vaccine simultaneously in lower cost and better immunization effect.

Key words: aquatic animal, immunity, oral, vaccine, forms