BACKGROUND: It was reported that one in four parents were hesitant about vaccinating their children in China. Previous studies have revealed a declining trend in the vaccine willingness rate in China. There is a need to monitor the level of parental vaccine hesitancy toward routine childhood vaccination and hesitancy toward the COVID-19 vaccine during the ongoing COVID-19 pandemic. OBJECTIVE: This study aims to assess changes in trends of parental attitudes toward routine childhood vaccines and COVID-19 vaccinations across different time periods in China. METHODS: Three waves of cross-sectional surveys were conducted on parents residing in Wuxi City in Jiangsu Province, China from September to October 2020, February to March 2021, and May to June 2021. Participants were recruited from immunization clinics. Chi-square tests were used to compare the results of the three surveys, controlling for sociodemographic factors. Binary and multivariable logistic regression analysis was used to examine factors related to parental vaccine hesitancy and COVID-19 vaccine willingness. RESULTS: Overall, 2881, 1038, and 1183 participants were included in the survey's three waves. Using the Vaccine Hesitancy Scale, 7.8% (225/2881), 15.1% (157/1038), and 5.5% (65/1183) of parents showed hesitancy to childhood vaccination (P<.001), and 59.3% (1709/2881), 64.6% (671/1038), and 92% (1088/1183) of parents agreed to receive a COVID-19 vaccine themselves in the first, second, and third surveys, respectively (P<.001). In all three surveys, "concerns about vaccine safety and side effects" was the most common reason for refusal. CONCLUSIONS: There has been an increasing acceptance of COVID-19 vaccination in Wuxi City, China. Effective interventions are needed to mitigate public concerns about vaccine safety.