The Paleogene period was a critical period of global climate transition. As a low-latitude inland basin, the Lanping Basin is located in the middle of the Tethys Ocean metallogenic belt, featuring diverse mineral species and abundant mineral resources. Currently, studies on the geochemical signatures and paleoclimate of this basin remain insufficient. The coupled evolution of tectonic activity and sediment supply during the Paleogene directly modulated paleoenvironmental frameworks and paleoclimatic evolutionary patterns, which bears great significance for constraining mineralization in this region. Taking the Paleogene clastic rocks of the Lanping Basin as the research object, through geochemical analysis of major elements, using weathering indices such as CIA and ICV and various structural-provenance discrimination charts, this paper systematically conducts research on Paleogene paleoenvironment and paleoclimate evolution, provenance attributes, and tectonic background in the source area. Results show that compared to PAAS, the major elements in the clastic rocks of the study area exhibit generally higher SiO₂ content, lower Al₂O₃ content, and significant differentiation in CaO, K₂O and Na₂O contents; Paleogene sources mainly come from the collision of the recycling orogenic belt; The tectonic background of the Yunlong Period was dominated by continental island arcs, with passive continental margin sources beginning to mix in during the Guolang Period, and completely transforming into passive continental margin by the Baoxiangsi Period; The chemical weathering effect of the Yunlong and Guolang Periods was weak, while the degree of weathering in the Baoxiangsi Period was significantly enhanced; The Paleogene climate evolved from arid conditions to a gradual transition between dry and wet climates, and finally to frequent seasonal dry-wet fluctuations under an overall arid background. The paleolake evolved from closed saline lake via semi-open alternating brackish-fresh lake to open freshwater fluvial-lacustrine facies. Co-evolution of paleoclimate, paleoenvironment, provenance and tectonics background supplies geochemical support for exploring metallogenic environment constraints on Yunlong Formation gypsum and Jinding Pb-Zn deposits.