Abstract: As one of China’s most economically active， open and innovative regions， the Yangtze River Delta boasts strategic significance in the country’s modernization. Immunization program has always been an important area of national and public concern， especially since the implementation of Law of the People's Republic of China on Vaccine Administration on December 1， 2019， with higher requirements for immunization program. With the support of state， governments and health administration departments of Shanghai， Jiangsu， Zhejiang and Anhui， the integration of immunization program in the Yangtze River Delta is imperative. Centers for disease control and prevention in Shanghai， Jiangsu， Zhejiang and Anhui provinces are closely linked， actively and steadily promoting rapid development of the integration of immunization program in the Yangtze River Delta， with Shanghai playing a leading role and Jiangsu， Zhejiang and Anhui playing their own strengths respectively. It is expected to establish a scientific， standardized and warm immunization program service system， and build a nationally leading and globally outstanding model area in integrated development of regional immunization program.