AIMS: Small for gestational age (SGA) is a prevalent issue in global public health. The relationship between SGA and neurodevelopmental delay remains a topic of debate and the exploration of potential biomarkers is crucial. The identification of placental-brain axis genes offers novel perspectives for anticipating neurodevelopmental delay. MAIN METHODS: First, we utilized multiple logistic regression to assess Ages and Stages Questionnaire of China (ASQ-C) scores in children at 6 months, 18 months, and 48 months of age. Next, we analyzed the placental transcriptome data from SGA and appropriate for gestational age (AGA) children in the Ma'anshan Birth Cohort (MABC) and validated it through Real-time quantitative PCR (RT-qPCR). Finally, we combined the experimental data with clinical data to establish a predictive model. KEY FINDINGS: SGA children were found to have a higher risk of neurodevelopmental delay at 6 months and 18 months of age. Further experimental validation found that decreased RPS27A gene expression was associated with developmental delay in solving-problem and personal-social domain at 6 months of age in SGA children. SIGNIFICANCE: Our study focused on the neurodevelopmental results of children from three time points, analyzed the mechanism of neurodevelopmental delay in SGA from the perspective of placenta-brain axis, and conducted experimental verification of the selected biomarkers. Therefore, our study has certain novelty and persuasive, providing new insights for early detection of neurodevelopmental delay in children with SGA.