been an essential development task for preschool children. This study analyzes preschool children’s discourse in the project-based learning (PBL) process and presents the following findings. Firstly, in the collaborative dimension, the frequency of children’s discourse on establishing and maintaining shared understanding (U) and taking appropriate action to solve the problem (A) is relatively high, while that on establishing and maintaining team organization (O) is relatively low. Secondly, in the problem solving dimension, the frequency of children’s discourse on planning and executing (P&E) is the highest, while that on monitoring and reflecting (M&R) is the lowest. Thirdly, in terms of turn taking patterns, self-selection accounts for a significantly higher proportion than allocation and continuation. Overall, preschool children’s CPS is characterized by loose collaboration and multilinear problem solving. They are usually keener to strive for opportunities to express their views but lack attention to others’ speeches. At the same time, they can constantly come up with new problem solving plans and actions but rarely reflect on their feasibility and actual effects. In addition to children’s collaborative role, teachers’ intervention can also impact the CPS processes. Therefore, teachers are recommended to provide children with opportunities for CPS and strengthen monitoring, guidance, and support in children’s CPS processes to facilitate better child engagement in CPS.