The rapid acceleration of polar ice sheet melting under ongoing global warming represents a critical tipping point in the Earth's climate system, with profound implications for sea level rise and large-scale atmospheric and oceanic circulation. While modern observations suggest that ice sheet retreat may significantly alter the East Asian monsoon (EAM) system, the long-term impacts and underlying mechanisms remain poorly constrained, particularly concerning the differential responses of the summer and winter monsoons. Here, we present a high-resolution, multi-proxy record from the Baxie (BX) section in the western Chinese Loess Plateau (CLP), where Rb/ Sr and magnetic susceptibility serve as proxies for the East Asian summer monsoon (EASM), Zr/Rb and grain size trace the East Asian winter monsoon (EAWM). Our results reveal a divergent evolution of the two monsoon subsystems since the onset of the Holocene: the EASM remained weak during the early Holocene and only intensified markedly after similar to 8 ka BP, while the EAWM began a sustained weakening from similar to 11.5 ka BP onward. We propose that residual Northern Hemisphere ice sheets suppressed the early Holocene EASM by maintaining high surface albedo and inhibiting northward moisture transport. Meanwhile, their progressive retreat weakened the meridional temperature gradient and the Siberian High, driving a long-term decline in EAWM strength. These findings provide new paleoclimatic constraints on the seasonal evolution of the EAM and emphasize the need to pay close attention to the impacts of ongoing high-latitude ice sheet retreat on future monsoon dynamics.