Amidst the intensifying global technological competition, the cross-regional flow of technological factors has become the core driving force for optimizing industrial structures and driving industrial transformation and upgrading. Grounded in the theoretical framework of "dual-circulation linkage" and "structural support", the synergistic enhancement mechanism governing cross-regional technological factor flows under the new dual-circulation development paradigm was elucidated. Based on multi-source patent transfer data covering 283 Chinese cities for the period from 2007 to 2023, a three-dimensional measurement system for industrial upgrading was constructed, and the interaction between international technology inflows and domestic technology outflows was empirically examined. Significant synergies are identified between these two flows. Domestic technology outflows are shown to exert a prominent structural supporting effect on industrial upgrading induced by international technology absorption, primarily by bolstering regional technological absorption and re-innovation capabilities. Empirical evidence is thereby provided regarding the path dependence risks inherent in exclusive reliance on technology introduction. Heterogeneity analysis reveals that the dividends of technology transfer are more readily harnessed in regions southeast of the "Hu Huanyong Line", where mature innovation ecosystems prevail. A double-threshold characteristic of domestic technology outflows is confirmed through further threshold tests, and the dynamic evolution process of technological factors from fragmented input to systemic integration is revealed. A gradient regional governance system and institutional opening-up strategies are proposed to mitigate insufficient value chain progression and uneven regional technological development. Theoretical support and practical pathways are thus offered for steering the deep coupling of innovation chains and industrial chains under the dual-circulation linkage framework.