Abstract: A new type(Model FCY-4)of steam sterilizable dissolved oxygen electrode has been successfully elaborated in our laboratary. It is mainly suitable for small fermenters. Numerous performance tests has been carried out, the results showed that the specifications of this model of DO electrode are nearly the same as that of the electrode imported. After applying this DO electrode to various fermenters, we found that the DO change monitored by this electrode had a good conformity with that of the foreign DO electrode.