A total of 23 cellulase producing marine bacteria had been isolated from Ningbo Sea area by the CMC/Congo Red method. Then the alkaline cellulase producing strain MB117 had been made an intensive study of its production of cellulase. According to the 16S rDNA analysis, the strain belonged to the Pseudoalteromonas sp.. The optimum initial pH of culture medium for the cullulase production was 7.0. And with 1% inoculum and 10% broth content, the maximum production of cellulase can be obtained. Low temperature is good for the growth and cullulase producing of MB117. The optimum pH for cellulase activity was 9.0, and the strain has a high enzyme activity and a good stability in the basic conditions. The optimum temperature for cellulase activity was 40 ℃.