The extracellular catechol 1, 2-dioxygenase was immobilized. The apparent activity of the immobilized extracellular catechol 1, 2-dioxygenase was high. and range of use was extended. The pH-activity profile was altered by immobilization, and optimal PH from 6.0-9.0 was observed. Immobilization was shown to increase the thermal stability of the enzyme.The pureness and concentration of biotrans-formation of catechol to cis, cis-muconic acid were high. The product was easily separatedfrom enzyme. The immobilized method of extracellular catechol 1,2-dioxygenase was novel and simple. The results presented show that the immobilization of extracellular catechol 1,2-dioxygenase offers an attractive means for the production of cis, cis-muconic acid.