Barium isotope compositions (S138Ba) represent a novel tracer for elucidating complex interactions between marine Ba cycling dynamics, paleoproductivity, and seawater redox evolution in ancient oceans. Here we present integrated S138Bacarb values and Ce/Ce* ratios from Lower Cambrian carbonates (Yurtus Formation, Xiaoxigou section, Tarim Basin). The studied carbonates record substantial S138Bacarb variations (-0.46 %o to +0.69 %o), with three prominent negative excursions interrupting baseline values comparable to modern open-ocean signatures. In combination with Ce/Ce* and S13Ccarb data, we interpret that the two stratigraphically lower negative S138Bacarb excursions, synchronized with a negative S13C shift, correspond to a transgressive event involving incursions of deep anoxic seawater. In contrast, the third negative S138Bacarb excursion, coincident with a positive S13C shift, points to the expansion of deep-water anoxic/euxinic conditions coupled with enhanced organic carbon burial. These findings collectively suggest highly dynamic barium cycling in the early Cambrian seawater of the northwestern Tarim Basin, with active, modern-like barium cycling in shallow waters episodically disrupted by incursions/upwelling of anoxic deep waters. Notably, while elevated Ce/Ce* ratios generally correspond to S138Bacarb decreases, the decreasing Ce/Ce* alongside sustained S138Bacarb decline during the third S138Bacarb excursion highlights decoupled redox evolution between shallow and deep water masses. While lowered Ce/Ce* values imply intensified oxygenation in shallow marine settings, synchronous increase in S13Ccarb and decrease in S138Bacarb collectively argue for the expansion of anoxic-euxinic conditions in deeper water masses. The coupled S138Bacarb and Ce/Ce* systematics thus provides complementary constraints for resolving redox evolution across vertically stratified water masses.