Using 2003–2006 RCRE (Research Center for Rural Economy) panel data, we estimate the effect of parental migration on the health of children left behind, with a difference‐in‐differences and propensity score matching combined model. On average we do not find any significant effect on children's health; however, the effect varies among different groups. Children's health may improve as a result of parental migration in families with lower income in the base year and families with higher‐income growth rates. Furthermore, children's health may deteriorate with maternal migration but improve with longer distance of paternal migration and longer time of paternal migration. We argue that parental migration affects children's health through complex mechanisms: income increase may have a positive impact while decreased parental care may have a negative effect. The two effects seem to offset each other in rural China.