The strain inherent in caregiving relationships between adult children and aging parents is a prominent issue in contemporary China due to a combination of demographic and socioeconomic changes. The purpose of this study was to explore how mutuality, a positive quality of caregiving relationships, contributes to the physical health and mental health (health-related quality of life [HRQoL]) of adult child caregivers [ACCs] of parent stroke survivors. A cross-sectional correlational study was conducted on a nonproportional quota sample of 126 ACCs, using questionnaires of demographics, the 15-item Mutuality Scale, and the Second Version of the Standard 12-Item Health Survey (SF-12v2). Higher mutuality was found to be correlated with better caregiver physical health and mental health. However, after adjusting for the covariates, mutuality significantly explained 4.6% of the variance of caregiver physical health (β = .22, ΔR2 = .046, p < .01) but it did not significantly explain the variance of caregiver mental health. Although multiple factors correlate with Chinese family caregivers’ HRQoL, this was the first study exploring the impact of caregiver–care receiver dyadic relationships on caregiver HRQoL in mainland China by using a mutuality scale with SF-12v2. Despite the fact that the Chinese tradition of filial piety can facilitate mutuality, socioeconomic changes and legislation that require adult children to care for aging parents appear to create high stress among family caregivers. Higher levels of mutuality contribute to better physical health in Chinese family caregivers. Therefore, culturally appropriate family nursing strategies and social policies in China could enhance caregiver mutuality and potentially promote their HRQoL, in particular physical health.