Abstract: PM_2.5 samples were collected from March 2015 to February 2016 in Dianshan Lake area, Shanghai. The characteristics of the carbonaceous compositions in atmospheric particulates during haze days were studied. The results showed that the annual mean concentration of PM_2.5 was (69.01±37.05)μg/m³, and the statistically significant correlations between PM_2.5 and organic carbon (OC), elemental carbon (EC) and water-soluble organic carbon (WSOC) in haze days, respectively. The degree of the correlations was associated with the degree of haze pollution. The annual mean concentrations of OC and EC were (4.46±3.41)μg/m³ and (2.15±1.31)μg/m³, respectively. The mean concentrations of OC and EC were high in winter and low in summer. The significant correlations between EC and OC were found during haze days and the degree of the correlations was also associated with the degree of the haze pollution. OC and EC were likely from the same sources and the contribution of secondary organic carbon (SOC) couldn’t be ignored. The mean concentrations of both non-volatile organic carbon (NPVOC) and volatile organic carbon (PVOC), defined by this study, followed the trend of high in winter and low in summer. The mean concentration of NPVOC was greater than that of PVOC. The mean concentration of char-EC was much greater than that of soot-EC, which indicated that char-EC was the main composition of EC. The annual mean concentration of WSOC was (2.07±1.40) μg/m³, but the mean concentration was higher in spring than that in winter, and the mean concentration in haze days were higher than those in non-haze days. The research also indicates that carbonaceous compositions could affect the atmospheric visibility, the pollution hence caused by carbonaceous compositions should be controlled.