In this paper, the addition of sodium carboxymethyl cellulose (NACMC) and cobalt ions to alginate gel significantly improved the inner and outer surface properties of membranes and the activity of the enzymes. The results showed the optimization was sodium alginate (SA) and NACMC at ratio 1:1, and the concentration of CoCl2 at 0.05mol/L. The combined SA-NACMC gel bead apparently had a more porous and higher mechanical strength than that of the SA gel bead by scanning electron microscopy (SEM). The microcapsule surface roughness was measured by atomic force microscopy (AFM), the roughness was 155±15.82mm. Otherwise, the Brunauer–Emmett–Teller (BET) analysis showed that with the addition of NACMC the surface area and most of pore size of the microcapsules was 76.471m2/g, and distributed in 3–25nm, respectively. In 28d, immobilized enzyme had a higher degradation rate, and the atrazine residue of the immobilized enzyme with 5% content was 21.79%.