Parents influence the physical activity (PA) of the childhood cancer survivors (CCS). This mixed-methods study, aiming to obtain an understanding of Chinese parents' perceptions of PA in CCS and how the cancer experience changes their views, which may affect these children's PA engagement. A mixed methods study was conducted at two hospitals in Hangzhou. A qualitative investigation using the thematic descriptive phenomenological approach analyzed data concerning the parents of 9-18-year-old childhood cancer survivors who had completed hospitalized treatment for at least three months. A cross-sectional investigation examined the association between parents' attitudes and children's PA levels using unconditioned binary logistic regression analysis. The qualitative investigation included 35 parents (74.3% female). More than half of the parents understood the benefits of regular PA. Most parents supported children's participation in low-intensity PA, but opposed high-intensity activities. Many parents changed their parenting style after cancer diagnosis, which might affect the development and persistence of children's PA. In the cross-sectional investigation, CCS were more likely to engage in low-level moderate-to-vigorous physical activity (MVPA) or less MVPA when receiving less paternal support (adjusted OR = 0.92, 95%CI:0.88-0.96) and maternal support (adjusted OR = 0.91, 95%CI:0.87-0.95). Insufficient paternal MVPA engagement (adjusted OR = 3.83, 95%CI: 2.57-5.70) and maternal MVPA engagement (adjusted OR = 5.65, 95%CI: 3.74-8.54) were associated with lower MVPA engagement in CCS. This study identified the understanding of parents of childhood cancer survivors concerning PA engagement and related life changes brought about by cancer experiences from the parental perspectives. These changes affect parental attitude towards children's participation in PA, and parental attitude and behavior affect children's participation in PA. Based on the above findings, some tentative practical implications for physical activity participation among childhood cancer survivors are drawn: (1) childhood cancer survivors should be encouraged to participate in more MVPA and consult a rehabilitation physician if necessary
(2) parents and children engage in exercise together is an important way to promote the levels of physical activity among childhood cancer survivors
(3) Chinese parents have insufficient awareness of the benefits of childhood cancer survivors participation in physical activity. We should strengthen health education for parents, promote parents to support childhood cancer survivors participate in physical activity.