Objective To investigate temporal variation in the abundance of total Vibrio parahaemolyticus in shellfish farm in Qingdao. Methods The abundance of total V.parahaemolyticus in shellfish and farm environment was detected using the most probable number real-time polymerase chain reaction(MPN real-time PCR) method during June 2013 and May 2014, and the correlation between V.parahaemolyticus abundance and the season was analyzed. Results The lowest level of MPN in shellfish and seawater presented from January to March,increased slowly before June,then rapidly rised up and reached the highest level until Augest. After that,it deceased rapidly to the lowest level in January. The lowest level of MPN in sediment was in March and the highest level kept from May to December(18 067.5-24 000.0 MPN/g),then dropped rapidly in January, and reached the lowest level in March(88.0 MPN/g). Conclusion Compared with the traditional methods, MPN-PCR has better sensitivity in reflecting V.parahaemolyticus growing trend with the the season and tempreture change.The level of bactiera abundence in oyster and seawater can be accurately assessed,which might play a role of early warning.The rapid growth time of V.parahaemolyticus in seawater and oyster is from June to Augest, which should be taken notice in the process of handling and eating to avoid foodborn disease.