This study aims to investigate the chemical characteristics and spatiotemporal variation of PM2.5 and also identify its promising sources in industrial complexes of southern Kaohsiung. Seasonal 12-hr PM2.5 samples were collected simultaneously at three sampling sites. The results showed that high PM2.5 concentrations were observed mainly in winter and spring. The PM2.5 concentrations at the downwind sites were always higher than those at the upwind sites because secondary aerosols were blown towards downwind sites by prevailing winds. Water-soluble ions (WSI) accounted for 31.4-56.8% of PM2.5, and secondary inorganic aerosols (SIA) (SO42-+NO3- +NH4+) dominated the WSI in PM2.5. High mass ratios of SIA/PM2.5 were also observed in winter and spring, suggesting that high-level PM2.5 was mainly contributed from SIA. PM2.5 was acidic particles since the neutralization ratio (NR) 0.1 and sulfur oxidation ratio (SOR) >0.25 showed that SIA formed commonly in winter and spring. Metallic elements accounted for 12.0-20.2% of PM2.5 with a tendency of daytime > nighttime. Enrichment factors (EF) showed that trace metals (Ni, Cr, Cu, and Zn) came mainly from anthropogenic sources. Carbonaceous content accounted for 9.3-24.3% of PM2.5. High mass ratios of organic and elemental carbons (OC/EC) were also observed in winter and spring. Moreover, the mass ratios of malonic and succinic acid (M/S) were always higher than 1.0 in winter and spring and lower than 1.0 in summer and fall, suggesting that organic acids dominated SOA in winter and spring. Major sources of PM2.5 in Linhai industrial complex were steel plants, and followed by secondary sulfate and nitrate, vehicular exhausts, petrochemical plants, and incinerators.