| Abstract: The research of the relationship between organic carbon isotopes composition of loess-paleosol sequence and paleo-vegetation and paleoclimate has great significance for the reconstruction of quaternary environmental change process. However, the research on the organic carbon isotope composition of Harbin loess in Northeast China has not been carried out. In this paper, we analyzed the organic carbon isotope composition and magnetic susceptibility of the loess-paleosol sequence of Harbin Huangshan core. The results show that the average organic carbon isotopic compositions in the paleosol and loess layer since the Middle Pleistocene are –24.8 ‰ and –25.1 ‰. On the whole, the organic carbon isotope composition of the paleosol layer is more positive than that of the loess layer, while the S0 and S2 paleosol layers are relatively negative. The relative abundance of C3/C4 plants in the past is restored by the end element method, which revealed that C3 plants are dominant in the study area since the Middle Pleistocene. Through the coupling comparison with sea surface temperature, deep-sea oxygen isotope and organic carbon isotope of Chifeng loess in Northeast China, it is found that the change of organic carbon isotope composition in Huangshan core is positively correlated with temperature, indicating that temperature is the main controlling factor of the change of plant carbon isotope composition. However, during some interglacial periods, such as the S0, S2 paleosol layer and the middle of S3 paleosol layer, precipitation may be a major factor. The above study shows that the response of plant growth to climate in Northeast China is complex. These understandings have important reference significance for the growth factors of C3 plants in Harbin.