Soil respiration is a major exchange channel of carbon between terrestrial ecosystem and atmospheric environ- ment; it plays a vitally important role in global carbon cycle and carbon balance. Under the background of global change, the issue of acid rain caused by anthropogenic activities has been serious increasingly; and the effects of increased acid rain on soil respiration have attracted increasing attention all over the world in recent years. Acid rain leads to soil acidification, and it then affects the metabolic activity of soil microbes, root growth, and litter decomposition, etc.; which finally affects soil respiration. This paper reviews the progresses of studies on the effects of simulated acid rain on soil respiration in forest and cropland ecosystem,and there are three kinds of results for the effects: depression, promotion, and no effect. The dif- ferent results are affected by experimental, biological and non-biological factors, including the experimental acidity and du- ration of simulated acid rain, vegetation type, plant growth season, vegetation succession phases, and physical and chemi- cal properties of soil, etc. Both the low and high intensity of acid rain tends to reduce the temperature sensitivity (Q_(10)) of soil respiration. This paper also analyzes the potential mechanisms of how acid rain affects the soil respiration in ecosystem from four key biological factors affecting soil respiration, including photosynthesis, litter, microbes and root biomass. How- ever, the process of the effects of acid rain on soil respiration is complex, leading to some uncertainties of the response mechanism of soil respiration to acid rain. Accordingly, some deficiencies for the current studies are summarized, and then four directions are proposed to be considered in the future study: (1) The studies on the responses of soil respiration to acid rain in different ecosystems; (2) The studies on the responses of different components of soil respiration to acid rain; (3) The studies on the combined effects of acid rain and other external factors; (4) The studies on the responses of biological factors that are relevant to soil respiration to acid rain.