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Paleoclimate significantly influenced continental sandstone-type uranium mineralization. To better understand continental climate change in the Late Cretaceous and its influence on uranium mineralization, we selected four boreholes from Late Cretaceous sedimentary successions from the southwestern Songliao Basin, in northeastern China. Twenty-one samples were collected for sporopollen analyses. Based on the variations in the relative abundances of the different sporopollen taxa, we observed the four following palynological assemblages (PAs) in ascending order: the Schizaeoisporites-Classopollis-Tricolporollenites assemblage, the Taxodiaceaepollenites-Exesipollenties-Cranwellia assemblage, the Schizaeoisporites-Classopollis-Lytharites assemblage, and the Biasccate-Taxodiaceaepollenites-Aquilapollenites assemblage. Based on the geological range of several important elements and correlations between relevant assemblages from other regions, we assigned a geological age of late Turonian to early Campanian (approximately 86.7-84.4 Ma) to the four PM. In this study, we introduced a sporopollen climate transforming methodology, which uses the percentage of drought, hygrophilous, and thermophilic taxa to indicate stratigraphic trends of humidity and temperature. On the one hand, the percentage of thermophilic taxa was characterized by a continuously decreasing trend, but remained at a relatively high abundance along the entire sedimentary sequence. This was indicative of a hot subtropical tropical climate with declining temperatures. On the other hand, the percentage of drought and hygrophilous taxa exhibited a cyclical fluctuation between humid and semi-arid climates. A semi-arid climate existed in the PA I, but this then changed to humid conditions in the PA II. Subsequently, the climate evolved into semi-arid and semi-humid conditions as a result of strengthened drought during the PA III. Finally, in the PA IV, the climate became humid once again. In general, the Yaojia Formation's synsedimentary paleoclimate (i.e., the PA II and PA III) mainly had semi-humid conditions. In the Qianjiadian area, the main prospect target layer is the Yaojia Formation. Compared with the typical sandstone-type uranium deposits throughout northern China, we suggest that the humid paleoclimate was essential for uranium mineralization. The humid climate favored the formation of reduced sandstones, which provided significant geochemical reducing barriers and uranium pre-concentrations essential for epigenetic uranium mineralization.