PM10-2.5 and PM2.5 samples were collected from December 2007 to January 2008 at six sampling sites in Urumqi Xinjiang, China. The concentrations of seven kinds of water-soluble ions––SO4 2-, NO3-, Cl-, NH4 +, K+, Na+, and Ca2+––were analyzed using ion chromatography. The concentrations of heavy metal elements, Cr, Co, Cd, Pb, and Hg were measured using inductively coupled plasma mass spectrometry (ICP-MS). The results indicated that, in PM2.5 and PM10-2.5, the average mass concentration of seven kinds of water-soluble ions were from 1.00 μg m-3 to 59.9 μg m-3 and 0.45 μg m-3 to 44.7 μg m-3, of which SO4 2- was the most abundant water-soluble ion, accounting for 30.2% and 26.5% of the total ion concentration in PM2.5 and PM10-2.5 respectively. High enrichment factor values (EF>50) were obtained for Cd, Pb, and Hg reflecting the importance of anthropogenic inputs.