A vermiculite/poly(2-acrylamido-2-methyl-1-propanesulfonic acid-co-acrylic acid) (VMT/P(AMPS-co-AA)) superabsorbent composites was prepared in aqueous solution by glow-discharge electrolysis plasma (GDEP) as initiator and N,N'-methylene-bis-acrylamide as a cross-linker. The reaction parameters affecting the equilibrium swelling (i.e., discharge voltage, discharge time, vermiculite content, and content of crosslinker) were systematically optimized to achieve a superabsorbent composites with a maximum swelling capacity. The structure, thermal stability and morphology of VMT/P(AMPS-co-AA) were characterized by FT-IR, XRD, TG and SEM. In addition, a possible copolymerization mechanism initiated by GDEP was proposed. The results showed that AM and AMPS monomers have grafted onto VMT successfully by GDEP forming an amorphous composite. The VMT/P(AMPS-co-AA) exhibits a rough and porous structure with visible wrinkles and has a higher thermal stability. Copolymerization mechanism initiated by GDEP is a free radical reaction process.