A new technique for the green-state joining of alumina ceramics without paste has been developed. Wetalumina green body, gelcast by PIBM (a copolymer of isobutylene and maleic anhydride) gel system, is used as a parent green body. The joining process involves integrating two wet green bodies in a gelling state, followed by drying and sintering. For example, wet green bodies after aging 10h were joined, and the joint region of the dried and sintered sample exhibited a homogeneous microstructure without defects or an interlayer. The flexural strength of the joined sample (468.5 +/- 62.9MPa) was nearly equivalent to that of a monolithic sample (470.6 +/- 27.4MPa). The joining mechanism was discussed on the basis of interaction among PIBM molecular chains. The proposed joining technique is simple and promising for producing advanced ceramics with large sizes and/or complicated shapes.