China started to offer a booster dose of COVID-19 vaccine to members of the adult population in October 2021. This study investigated the behavioral intention to receive a booster dose of COVID-19 vaccine among factory workers who had completed their primary vaccination series. Participants were full-time factory employees at least 18 years of age in Shenzhen, China. In Shenzhen, factory workers need to receive a physical examination every year. The study sites covered all six organizations providing physical examinations for factory workers. All eligible workers attending these sites between 26 and 31 October 2021 were invited to complete an online survey. This study was based on 2329 participants who had completed the primary COVID-19 vaccination series. Two-level logistic regression models were fitted. Among the participants, 84% intended to receive a free booster dose of COVID-19 vaccine within the next six months. After controlling for significant background characteristics, we found that perceptions related to a booster dose as well as interpersonal level factors such as information exposure on social media, thoughtful consideration of the veracity of the information, and satisfaction with vaccine-related promotional materials were determinants of behavioral intention. Factory workers in China reported a high level of behavioral intention to receive a booster dose of the COVID-19 vaccine.