Chronological study of sandstone type uranium deposits is an important part of uranium mineralization mechanism research and a key to revealing the evolution laws of uranium mineralization. Currently, there is a large amount of data on uranium mineralization chronology in the Songliao Basin, but some of the data have poor reliability or even errors, leading to some erroneous understandings and conclusions. Methods:By integrating previous and self measured uranium lead isotope data from three uranium deposits in the southwestern Tongliao area of the Songliao Basin, namely Qianjiadian, Dalin, and Hailijin, and using an improved whole rock isochronous age fitting method, the uranium mineralization age was re fitted and calculated. Results:The results indicate that the three deposits have consistent uranium mineralization periods, which can be divided into 10 periods: Yaojia Formation sedimentation period, Nenjiang period, Sifangtai period, Mingshui period, Middle Paleocene, Late Paleocene, Middle Eocene, Late Eocene, and Middle Oligocene. Conclusions:The uranium mineralization mainly occurs within several million years after strong compressional tectonic activity, and the ages of uranium mineralization in each stage are consistent with the ages of apatite fission track and magmatic rock, showing the characteristics of "episodic" stage mineralization. The uranium mineralization of the Upper Cretaceous began at the beginning of the structural inversion in the Songliao Basin (88.5 Ma), and each mineralization is related to the strong tectonic dynamics of the region. It is believed that the genesis of gray mudstone and sandstone in the red variegated rock layers is closely related to the overflow of deep- seated reducing fluids. The favorable prospecting locations are the fluid trap systems formed by faults, folds, and sand bodies on the upper or upper edges of the source rock layers. Red variegated layers such as the Nenwu Member, Sifangtai Formation, Mingshui Formation, and Paleogene have prospecting potential.