There is little understanding about the effects of adult child migration on the health of elderly parents left behind in the light of economic contribution and time allocation (farm work and emotional cohesion). Using the pooled data from three latest issues of China Health and Retirement Longitudinal Study (CHARLS) in the rural areas, this study assesses the impact of child migration on parents’ health by employing instrumental variable approach to deal with the endogeneity problem. Overall, the evidence suggests that adult child migration impairs parental health as indicated by lower self-reported health (SRH), body mass index (BMI), physical activity of daily living (PADL), and higher depression score. Moreover, parents who are female, poorly-educated, and living with one adult child at least are the most vulnerable groups in terms of poor health outcomes. The negative impact of farming burden on the health of parents left behind outweighs the positive impact of economic support and emotional cohesion. Thus, child migration exerts a significantly negative impact on parental health. Establishing medical and social security systems for the elderly is important to complement the traditional family support in rural China.