ObjectivesA prospective study was performed to examine the relationship of childhood socioeconomic status (SES) with cognition and the rate of change in a nationally representative sample of community‐dwelling middle‐aged and older Chinese population.MethodsThis study mainly focused on 3 composite measures of cognitive function, including Telephone Interview of Cognitive Status, word recall, and drawing a figure successfully. Childhood SES was evaluated by parental occupation and education, childhood residence, and self‐evaluated financial status. We designed an analysis strategy adding predictors incrementally in different models to examine the changes of effects of childhood SES on cognition by latent growth curve models.ResultsFinally, a total of 10 533 respondents were prospectively studied, including 5980 respondents aged 45–59 and 4553 aged 60–90. Cognition in younger cohort showed a curvilinear change, while cognition in older cohort showed a linear decline. After controlling for covariates, middle‐aged respondents with higher self‐evaluated financial status (β: −0.22, P < .001), better health status (β: −0.13, P < .001), higher parental education (β: 0.17 and 0.10, P < .001), who had lived in city/town before 16 years (β: 0.69, P < .001), and whose fathers engaged in nonfarming work (β: 0.43, P < .001) were associated with the better baseline cognition. Similar results were found in older cohort. Additionally, early‐life SES was not associated with cognitive decline in both cohorts.ConclusionsThis study indicates that childhood SES is associated with mid‐life and late‐life baseline cognition, but it is not contributed to cognition decline. Interventions in early‐life focused on improving childhood SES might have positive impacts on baseline cognition in later‐life.