Abstract: 【Objective】Obtain the composite super absorbent polymer, and analyze its water holding capacity. 【Method】 Composite water-retaining agents were prepared with acrylic acid(AA), corn starch(CS), sodium alginate(SA), sodium bentonite(SB), ammonium persulfate(AP)as initiator, and N, N'-methylene-bis-acrylamide(MBA)as cross-linking agent by means of solution polymerization. The composite water-retaining agents were characterized by infrared spectrum, thermo gravimetry and scanning electron microscope. 【Result】Sodium alginate and sodium bentonite can improve the properties of water-retaining agent, while decrease cost of production. That water absorptivity of composite water-retaining agent having AP of 0.20% based on AA, MBA of 0.025% based on AA, SA of 15% based on AA and SB of 15% based on AA indistilled water and normal saline was 850 g/g and 95 g/g, respectively. 【Conclusion】This composite water-retaining agent had fast water absorption rate and good water retention capacity.