Abstract: Objective To investigate the effect of media report of illegal vaccine sales (IVS) in Shandong province in 2016 on attitude and behavior of parents about vaccination of their children in Tianjin city for implementing specific countermeasures. Methods An online survey on attitude towards vaccination was conducted among parents of preschool children from March 25 one week after the media report on IVS in Shandong province to April 7, 2016 in Tianjin city;data on vaccination status of vaccines free of charge (class A vaccines, CAVs) for children under one year old and charged vaccines (class B vaccines, CBVs) for children aged ≤7 years before and after mass media report on the IVS were collected from Tianjin Municipal Immunization Management Information System and analyzed simultaneously. Results The awareness rate of the IVS report was 98.81% among the 1 177 parents surveyed.Of the parents knowing the IVS, 53.44% and 25.32% got the IVS information via mobile phone media and online computer;76.64% knew that only some of CBVs were involved in the IVS reported.Of all the parents surveyed, 29.06% expressed the refusal of CBVs for their children in future;57.52% expressed the hesitation for their children to receive vaccination of CBVs;74.26% reported the worry about the safety of CAVs, with a significant difference in the ratio among the parents of children at various ages (χ²=11.95, P < 0.05);58.71% thought that IVS would not affect the vaccination of CAVs for their children in future, but 40.87% worried about the influence of IVS on the vaccination of CAVs.There was a significant difference in the influence of IVS on the attitude towards vaccination between the fathers and the mothers surveyed (Z=-2.03, P < 0.05).Compared with those of same period and average monthly vaccination rate in 2015, the coverage rate of CAVs decreased 1.47%-8.92% and 1.31%-5.44% during March 2016 among the children under one year old;the number of children aged ≤7 years receiving CBVs declined by 19.17% for inactivated polio, 42.80% for varicella, 33.21% for haemophilus influenzae type B, 30.71% for rotavirus, and 36.36% for pneumococcal vaccine, respectively. Conclusion The IVS in Shandong province had great influence on the confidence of the parents to vaccinations of their children and induced changes in the acceptance of vaccination among the children in Tianjin city.The results suggest that positive dissemination of information on vaccination should be promoted among the public to ensure the implementation of vaccination programs among the children.