Abstract: 369 strains of ETEC isolated from seven areas were tested for LT, ST h, STp, CFA Ⅰand CFAⅡ. T he results showed that ST -ETEC was the most frequently in these areas.Of ST - ETEC strains, ST p-only strains were predomination, followed by ST h-only strains. LT -ETEC strains were common in southern areas, however rarely found in northern areas. LT - only strains were not found ex cept Guangzhou and Haikou areas. Among 260 str ains of ETEC, CFA Ⅰand CFA Ⅱ wer e found in 50. 8%. We confirmed the observations of others that ST p ETEC are more frequently associated with CFAⅠ and CFA Ⅱ ex pression, however, in contrast to others, we found LT -only ETEC also associated with CFA Ⅰand CFA Ⅱ. CFA Ⅱ was the more frequently identified colonization factor than CFAⅠ. Bearing CFA Ⅰ strains was significantly frequent in southern areas than in northern areas. No significant difference was found in enterotoxin types among strains isolated fr om patients, healthy persons and environments.But a clear association was showed between diarrheal patients and CFAⅠand CFAⅡ.