Using the baseline data from China Education Panel Survey （CEPS）， this paper identified 8324 rural left-behind children （LBC） and non-left-behind children （NLBC）. Using OLS regression models with non-left-behind children as the reference group， the study first analyzes the impacts of perceived stress on the academic performance of LBC， examines its robustness and heterogeneity， and finally reveals the moderating role of teacher’s support in the aforementioned relationship. The results show that compared to NLBC， LBC exihibit significantly poorer academic performance and experience higher levels of psychological stress. The significant negative impacts of perceived stress on academic performance differs between LBC and NLBC； academic stress has smaller effect on the academic performance of LBC， while psychological stress has a larger effect， and both effects pass robustness test. The impacts of perceived stress on the academic performance of LBC are heterogeneous due to variations in family income and parental educational backgrounds， and perceived stress tends to negatively affect the academic performance of those with low family income and low parental education. Teacher’s support does not play a regulating role in the impacts of perceived stress on academic performance of LBC， but it significantly mitigates the negative effect of psychological stress on the academic performance of NLBC.