Abstract: Poly (acrylic acid) (PAA) and montmorillonite (MMT)/PAA superabsorbent resins were synthesized by partly neutralized acrylic acid (AA) and sodium type montmorillonite. The structure of the superabsorbents was characterized by FTIR,  XRD and SEM,  and its blood compatibility was measured by the hemolysis test,  coagulation time test and recalcification time test. The results show that montmorillonite layers reacted with acrylic acid during polymerization. The layers exfoliated and scattered in the composite at nano size after the polymerization. Both of the superabsorbent resins have good blood compatibility.