Over the last decades, numerous studies have used the loess-paleosol sequences in China to reconstruct the East Asian climate and to investigate their linkage with global climate change. The paleosols embedded in the loess developed during warm periods and contain valuable information on climate and vegetation under warm conditions. However, because soil formation is controlled by multiple factors, it is not straightforward to obtain a pure climate signal based on soil property analyses. This leads often to debates and questions. Here, for the first time, we use a soil formation model together with a climate model to identify the main factors that control the paleosol formation. A case study has been performed on paleosols in the Chinese Loess Plateau of the last interglacial (Marine Isotope Stage [MIS] 5e) and the interglacial at ca. 500 kyr B.P. (MIS 13). Our results show that although the peak warmth and peak summer monsoon precipitation are stronger during MIS 5e, the soil formation is stronger during MIS 13, which is supported by field evidence. This is mainly due to larger accumulative precipitation surplus, weaker dust deposition, and longer interglacial duration during MIS 13. Our results provide a new interpretation of the climate signal recorded by the paleosols, and an explanation for the seeming paradox that strongly developed soils formed during relatively weak interglacials. They also highlight the necessity to include proxy modeling in paleoclimate studies.