The provenance of loess sediments in the Chinese Loess Plateau has garnered extensive attention, raising a pivotal scientific question regarding whether their source regions underwent variations during glacial-interglacial cycles. However, limited studies have examined the provenance changes of Northeast China loess throughout the accumulation processes, particularly at the easternmost margin of the Eurasian loess belt. To address this gap, the Harbin loess from the eastern margin of the Songnen Plain is selected for provenance investigation by conducting heavy mineral analyses using the TESCAN Integrated Mineral Analyzer (TIMA) on both the loess profile and potential dust sources from the Northeast China sandy lands, in conjunction with FingerPro quantitative provenance analysis. Qualitative results revealed that the heavy mineral assemblages of the Harbin loess are similar to those of the Songnen Sandy Land (SN), indicating its primary contribution as a dust source. Quantitative provenance results demonstrated significant sediment source variations in the Harbin loess during the MIS 6, MIS 6/5 and MIS 5/4 transition periods. The dynamic variations of the atmospheric circulation, including summer monsoon (southwesterlies), winter monsoon (northwesterlies), low-level and high-level westerlies, are responsible for the dust provenance variations of the Harbin loess in the orbital and sub-orbital timescales. Specifically, the dust contribution of the Hulun Buir Sandy Land (HL) is controlled by the high-level westerlies and the East Asian Winter Monsoon, while the competing dust contributions between the Horqin and Otindag Sandy Land (HQ + OD) and SN are governed by the lower-level westerlies and the East Asian Summer Monsoon. Additionally, surface processes further modulate dust emission fluxes at suborbital scales through regulating sand-land boundaries and dust availability. The Songnen Plain should implement integrated measures to establish a dynamic prevention/control system and monitoring platform based on its unique "westerlies-monsoon-geomorphology" dust transport mechanism.