Objective To analyze the impact of incorporating a two-dose varicella vaccine in the immunization program in Yizheng City, Jiangsu Province on the epidemiological characteristics of varicella, and to provide a scientific basis for formulating and improving the varicella vaccine immunization program. Methods The descriptive epidemiological method was employed to compare varicella incidence data before (2018-2022) and after (2023-2024) the implementation of the immunization program. The reported incidence rate, and temporal, regional, population distributions, and changes in outbreaks were analyzed. Results After the implementation of the immunization program, the average annual reported incidence rate of varicella in Yizheng was 75.18/100 000, which decreased by 33.20% compared to the period before implementation (112.54/100 000). The reported incidence of varicella in Yizheng exhibited a bimodal distribution, with the main peak occurring from November to January of the following year and the secondary peak from May to July. The decrease in the reported incidence rate in males (35.97%) was higher than that in females (30.05%). The reported incidence rates significantly decreased in the 0-4, 5-9 and ≥25 age groups (decreased by 69.17%, 60.47% and 25.26%, respectively), but increased in the 10-14 age group (increased by 28.48%). Students consistently constituted the main affected population. After the immunization program, outbreaks in kindergartens and primary schools significantly decreased, and the coverage rate of the second dose increased from 2.99% to 96.37%. Conclusion The two-dose varicella vaccine immunization strategy significantly reduces the reported incidence rate and outbreaks among young children, but the reported incidence rate among adolescents shows an upward trend. It is necessary to continue to improve vaccination coverage and strengthen surveillance, prevention and control among adolescence.