Rivers play an important role in source- to- sink systems, with their sediments serving as key entry points for provenance analysis. U- Pb dating of detrital zircon in river sediments has become a widely used tool for studying drainage evolution, provenance tracing, and source- to- sink relationships. However, the factors influencing the U- Pb age distribution of fluvial- detrital zircons in high- latitude regions and their representation in provenance tracing studies have not been fully evaluated. This can lead to inconsistent results and potentially affect the accurate establishment of source- to- sink systems. This study focuses on the Jilin section of the Songhua River, analyzing a total of 780 zircon U- Pb ages from 6 river sediment samples, and quantitative constraints were applied using an inverse Monte Carlo model. The results reveal three dominant zircon U- Pb age peaks: 2500 Ma, 250 Ma, and 180 Ma. Additionally, the age distribution pattern of zircons shows significant variations from upstream to downstream. Specifically, the proportion of zircons with a characteristic age of 2500 Ma, derived from the northeastern margin of the North China Craton, decreases markedly in the upper and middle reaches. This suggests that the increased contribution of new provenance sources in the middle reaches has diluted the provenance signal from the upper reaches, potentially influenced by the interception effect of the Fengman Reservoir. Furthermore, the contribution from the northeastern margin of the North China Craton continues to decline in the middle to lower reaches, while the contribution from the Songnen and Zhangguangcai Range blocks increases, indicating the addition of new provenance sources during river transport. In the main stream of the Songhua River, a significant influx of zircon particles younger than 250 Ma, carried by the Nenjiang River, dilutes the 2500 Ma age signature characteristic of zircons from the second Songhua River. This study highlights that provenance signals vary significantly across different river reaches, and signals present in the upper reaches may be missing in the lower reaches. Consequently, using detrital zircon age data from river estuaries or a single sample to represent the provenance information of an entire catchment introduces some degree of uncertainty. In addition, the peak ages observed in the Jilin section of the Songhua River align with the tectono- magmatic thermal events of the eastern Central Asian Orogenic Belt. The 2500 Ma peak may represent of the consolidation of the North China Craton microcontinent, while the 250 Ma and 180 Ma peaks correspond to the closure of the Paleo- Asian Ocean and the subduction of the Paleo- Pacific Plate, respectively. This study provides significant insights into the source- to- sink processes in the Jilin section of the Songhua River and offers valuable reference data for understanding tectonic events in Northeast China.