Based on a data of northwest China from 2012 to 2023, this study employs quantitative methods to conduct a systematic assessment of the temporal and spatial evolution characteristics and the driving mechanism underlying the consolidation of poverty alleviation achievements. Furthermore, it explores strategic approaches for optimizing assistance policies in northwest China after the period of consolidating poverty alleviation. Results show: 1) From 2012 to 2023, the effectiveness scores of consolidating industrial poverty and ecological poverty alleviation in northwest China initially declined and then rose, showing a U-shaped evolution trend. The scores for consolidating cultural poverty alleviation first increased and then stabilized, while the scores for consolidating grassroots governance and prosperous living standards exhibited a fluctuating upward trend. Moreover, the scores for consolidating ecological poverty alleviation, cultural poverty alleviation and prosperous living standards were relatively high. 2) From 2012 to 2023, the overall effectiveness scores of the achievements of consolidating poverty alleviation in northwest China showed a fluctuating upward trend. There was a significant spatial disparity, presenting a “dumbbell-shaped” distribution pattern with higher scores in the east and west and lower scores in the central area. However, spatial distribution trend analysis indicates that the northwest China is gradually breaking this distribution pattern and developing towards a balanced state. And 3) the temporal and spatial evolution of the overall effectiveness of consolidating poverty alleviation achievements in northwest China is mainly driven by the synergistic effects of the five subsystems, among which the optimization of agricultural planting structures and the improvement in living conditions have relatively weaker driving forces on the overall system. Based on these findings, the study concludes that enhancing coordinated efforts to reinforce the unsubstantial drivers in consolidating poverty alleviation achievements, dynamically optimizing resource allocation for assistance programs in northwest China, and advancing equitable regional development should be prioritized as key policy measures.