Rainwater samples collected from Guiyang city in southwestern China between May 2009 and December 2010 were analyzed to measure their calcium and strontium isotope compositions. The results show that Ca2+ is the most abundant cation in these rainwater samples, while SO42- is the most abundant anion. Most rainwater samples are alkaline, with a volume-weighted mean (VWM) pH value of similar to 6.2 (a 1.2-unit increase since 2008). This can be explained by the neutralization of rainwater acidity by the dissolution of atmospheric aerosols in the form of calcium-rich soil and other anthropogenic dust, which are increasing because of rapid urbanization. Both stable (delta Ca-44/40 and delta(88)/Sr-86) and radiogenic (Sr-87/Sr-86) isotope compositions of rainwater show variations correlating with each other and with the inverse of Sr or Ca concentrations. They also correlated with the concentration ratio of (NH4+ + K+)/(Ca2+ + Mg2+)-an index reflecting the anthropogenic input relative to soil dust. Based on our results, three major reservoirs can be inferred to have contributed to rainwater chemistry in Guiyang city: (1) a carbonate aerosol source characterized by low Sr-87/Sr-86 (<=similar to 0.708), delta Sr-88/86 (<= similar to 0.32 parts per thousand) and delta Ca-44/40 (similar to 0.5 parts per thousand), very low (NH4+ + K+) / (Ca2+ + Mg2+), and low 1/Ca2+ and 1/Sr2+; (2) a silicate aerosol source characterized by relatively high Sr-87/Sr-86 (>= 0.717), delta Sr-88/86 (>=similar to 0.34 parts per thousand) and delta Ca-44/40 (similar to 0.8 parts per thousand), very low (NH4+ + K+) / (Ca2+ + Mg2+), low 1/Ca2+ and 1/Sr2+; and (3) an anthropogenic component containing low 87Sr/86Sr (similar to 0.708), delta Sr-88/86 (similar to 0.30 parts per thousand) and high delta Ca-44/40 (similar to 0.8 parts per thousand), and high (NH4+ + K+) / (Ca2+ + Mg2+). The chemistry of solutes in Guiyang rainwater can be explained by (1) dissolution of carbonate and silicate aerosols, as well as the anthropogenic inputs including seasonal farming activities; (2) tightened environmental protection regulations; (3) higher precipitation volumes in 2010; and possibly (4) the increased combustion of coal for heating and electricity in winter. This study demonstrated that a combination of elemental compositions, stable Ca and Sr, and radiogenic Sr isotope compositions in rainwater can be used to trace the sources of atmospheric aerosols.