Radiogenic strontium isotopes (87Sr/86Sr) in terrestrial archives are a powerful tool for reconstructing past environmental changes. However, their application in loess-paleosol sequences on the Chinese Loess Plateau (CLP) is often hampered by detrital contamination and stratigraphic complexities in pedogenic carbonates. Land snail shells, as in situ biogenic carbonates, offer a promising alternative. Here, we present a comprehensive dataset of 87Sr/86Sr from modern land snail shells (Cathaica sp.) and river waters along a climatic transect of the CLP. Our results reveal a distinct northwest-southeast increasing gradient in snail shell 87Sr/86Sr, a pattern mirrored by riverine 87Sr/86Sr, indicating a shared regional biogeochemical signal. This spatial trend is decoupled from the snail shell Sr/Ca ratios, which are primarily controlled by rainfall-mediated prior calcite precipitation. Instead, the 87Sr/86Sr gradient likely reflects a climate-driven shift in weathering regimes, from carbonate-dominated weathering under cooler, drier northwestern CLP to silicate-dominated weathering enhanced by warmer temperatures in the southeastern CLP. A strong correlation between Cathaica sp. shell 87Sr/86Sr and delta 13C further suggests a common temperature control, likely through its influence on both silicate weathering kinetics and C3 plant photosynthetic fractionation. We propose that Cathaica sp. shell 87Sr/86Sr may serve as a novel paleothermometer for loess deposits, providing an independent temperature proxy that complements existing hydroclimate indicators.