The open-pit coal mining areas in Inner Mongolia have been subjected to prolonged mining activities, leading to exposed ground surfaces and vegetation degradation. In conjunction with the region's arid and windy climate, dust deposition has emerged as a critical environmental stressor impeding the ecological restoration of these mining areas. Dust not only physically obstructs the photosynthetic functions of plant leaves but also potentially alters soil properties and disrupts the carbon-nitrogen metabolic balance in plants, thereby hindering the recovery of ecological functions and the carbon sequestration potential of reclaimed vegetation. Under the global carbon neutrality strategy, the ecological restoration of mining areas must focus not only on enhancing vegetation coverage but also on optimizing plant configurations to improve the ecosystem's carbon sequestration capacity. Currently, research on the impact of dust deposition on the photosynthesis of reclaimed vegetation predominantly examines short-term effects, with insufficient systematic comparisons of light adaptation strategies among different species. In order to explore the effects of dust deposition on the photosynthesis of typical reclaimed herbs in open-pit coal mines of Inner Mongolia, three typical pioneer species in reclamation, Medicago sativa, Astragalus adsurgens and Arrhenatherum elatius, were selected as test sites in Zahanauer Open-pit Mine. And the field control experiment was conducted to explore the changes of photosynthetic physiological characteristics of plants in a long-term dust settling environment. The results showed that: (1) Dust deposition limited the photosynthetic rate of the three herbaceous plants, and led to the reduction of photosynthetic characteristics parameters (dark respiration rate Rd, stomatal conductance Gs, transpiration rate Tr). Moreover, the longer the dust deposition time, the lower the photosynthetic rate of plants, and the higher the limiting degree of plant organic matter accumulation, and the most obvious limiting effect on Astragalus adsurgens. (2) The light saturation point of the photosynthetic curve of the three plants was basically the same under different dust duration. The light compensation point of Arrhenatherum elatius was slightly higher than that of Medicago sativa and Astragalus adsurgens, and the maximum net photosynthetic rate of Medicago sativa and Astragalus adsurgens was significantly higher than that of Arrhenatherum elatius. However, under the same dust duration, the bioaccumulation, net assimilation and carbon fixation and oxygen release of Arrhenatherum elatius were significantly higher than those of Medicago sativa and Astragalus adsurgens.(3) Medicago sativa and Astragalus adsurgens exhibit a broader range of light intensity adaptation and possess higher photosynthetic potential. In contrast, Arrhenatherum elatius demonstrates a stronger carbon fixation capacity and organic productivity under conditions of weak photosynthesis. Medicago sativa community growth competitiveness was prominent under dust settlement conditions, while Arrhenatherum elatius community growth competition was not superior under dust settlement conditions.The results provide theoretical basis and technical support for the implementation of ecological restoration and carbon neutrality regulation based on vegetation restoration of open-pit coal mines in Inner Mongolia.