Abstract: A strain of Escherichia coli O157H7 was isolated from imported freezed sea fish, using rapid antigen test, mini-Vidas enzyme linked immunofluorescent test and others in December, 1998. Some different charactersticts were found between this strain and those described in a variety of publications. It could ferment rhamnose and sorbitol rapidly, but could not ferment raffinose, melampyrin and MUG test was positive. So, other methods such as serologyical test should be used in our routine surveillance.