Soil respiration is the greatest carbon fluxes from terrestrial ecosystem to the atmosphere, and therefore any tiny changes in soil respiration could result in great impact on the global carbon balance. Due to anthropogenic activities, acid rain has been one of the most serious environmental problems, but its impacts on soil respiration and the underlying mechanisms remain inconclusive. This paper reviewed the responses of soil respiration to acid rain in different ecosystems, summarized and discussed the underlying mechanisms by which acid rain changes soil respiration. Results showed that strong acid rain suppressed soil respiration, while medium and low acids did not alter soil respiration consistently across studies. Four important biological factors including photosynthesis process, microbial communities, litter decomposition and root-productivity were discussed in details. Moreover, further studies in regard to acid rain effects on soil respiration could highlight in these aspects as listed below: 1) how different types of acid rain would affect soil respiration; 2) how acid rain would affect functional microbes and related genes involving the terrestrial C cycling; 3) whether soil respiration at different plant phonological stages would respond similarly to acid rain; 4) how different soil respiration components and related processes (e.g., autotrophic and heterotrophic soil respiration) would respond differently to acid rain; and 5) a global monitoring network should be established to further understand effects of acid rain on soil respiration across climatic zones and ecosystems in the acid rain affected areas.