An in-vivo self-assembly capsule system is disclosed, where the in-vivo capsule system comprises a first primary capsule, at least one second capsule, and a self-connection means for connecting the first primary capsule and said at least one second capsule by providing holding force when the first primary capsule and said at least one second capsule are in contact in human GI tract. The self-connection means comprises an interlocking means disposed on the first primary capsule and said at least one second capsule. The interlocking means may correspond to hooks disposed on one connecting side and loops disposed on another connecting side, or hooks disposed on both connecting sides. The interlocking means may also correspond to a first magnet and an interaction piece affixed to two corresponding capsules respectively, and the interaction piece corresponds to a second magnet or a ferromagnetic component.