The main purpose of this research was to describe the distribution of V.parahaemolyticus serotypes isolated from diarrhea cases and food in Shanghai and the molecular characteristics of pandemic strains.MethodsGS-PCR was used to recognize pandemic strains. tdh gene, trh gene and orf8 gene of phage f237were detected by PCR after serotyping. PFGE was used to analyze the genetic relationship among isolates. Results1136isolates were divided into 52serotypes (groups). 64.5% of all isolates were GS-PCR positivewhich wasthe pandemic strains. 11serotypes were found in pandemic strains in Shanghai, among which O3∶K6(76.8%), O4∶K68(9.4%), O1∶K25(6.8%), and O1∶K36(4.5%) were the main serotypes. Pandemic strains with serotypes of O10∶K60, O3∶K3and O1∶K33were first reported, and their PFGE patterns were closer to the reported pandemic strains. Most pandemic strains only had tdh gene, and no trh gene positive. Except 5.7% strains, most pandemic strains were positive for orf8gene.PFGE patterns were different among pandemic strains with same serotypes, and isolates with or without orf8 gene could not be distinguished by PFGE.ConclusionNew serovariants of pandemic were emerging, and the results of PFGE and orf8 gene detection suggested there was gene mutation amongpandemic strains.