Abstract: The Tantou Basin in western Henan is a Late Cretaceous-Palaeogene continental sedimentary basin in which the red clastic rocks are accentuated. The combination of palynological, palaeontological, petrological, sedimentological approaches in the present paper has disclosed that there occurred the semiarid tropical climates during the deposition of the lower member of the Gaoyugou Formation; semiarid to subhumid subtropical to tropical climates during the deposition of the lower part of the upper member of the Gaoyugou Formation, and subhumid subtropical climates during the deposition of the upper part of the upper member of the Gaoyugou Formation. Till the deposition of the basal part of the Dazhang Formation, the subhumid warm temperate climates prevailed over the study area. It is concluded that the Cretaceous-Palaeogene boundary should be delimited in the strata between the upper part and lower part of the upper member of the Gaoyugou Formation.