The objective of this study was to describe the fertility intentions and the possibility of having a third child of participants in Guangxi Zhuang Autonomous Region since the "three-child" policy was adopted in China and to explore factors associated with intentions to have a third child. This study was conducted among 1525 participants from five universities using a questionnaire from September to November 2021 in Guangxi, China. Data were collected on the student's sociodemographic characteristics and fertility intentions. A descriptive analysis, chi-square test, difference test and ordered logistic regression model were used for data analysis. The ideal number of children among the participants in Guangxi was 1.89 ± 0.52, and the average number of planned children was 1.49 ± 0.88. Although the policy encouraged having a third child, fewer than a tenth (5.5%) of participants clearly intended to. More than 15% (17.6%) of participants clearly intended not to have child. Compared with female participants, male participants had more planning number of child (P value = 0.003) and were more likely to have a third child (P value = 0.000). The earlier participants get married the more likely to have a third child (P value = 0.000). Compared with urban participants, rural participants were more likely to have first and second children (P value = 0.003), but there was no significant difference in the possibility of having three children. Participants show lower fertility intentions and less likely to have third child under the "Three-child" policy. More fertility intentions' researches and supplementary measures are urgently needed to improve fertility rates in China.