In order to quantify the aerosol impact on climate, a range of aerosol parameters are required. In this paper, two-year of ground-based observations of aerosol optical properties from an urban site in Beijing of China are assessed. The aerosol absorption coefficient (σ<sub>a</sub>), scattering coefficient (σ<sub>s</sub>), as well as single scattering albedo (ω) are analyzed to aid in characterizing Beijing's urban aerosol. Two-year averages (and standard deviations) for σ<sub>a</sub> at 532 nm, σ<sub>s</sub> at 525 nm and ω at 525 nm are 56±49 Mm<sup>−1</sup>, 288±281 Mm<sup>−1</sup> and 0.80±0.09, respectively. Meanwhile, there is a distinct diurnal variation for σ<sub>a</sub>, with its minimum occurring at approximately 14:00 to 15:00 and maximum at midnight. σ<sub>s</sub> peaks in the late morning and the minimum occurs in the evening. σ<sub>s</sub> in summer is higher than that in winter. ω is also higher in summer than that in winter, except before 07:00 a.m., and peaks in the early afternoon. Both σ<sub>a</sub> and σ<sub>s</sub> show strong dependence on local wind in all four seasons. When the wind blows from the north with low speed (0–2 m/s), the values of σ<sub>a</sub> are high, and in contrast, very low with wind speeds higher than 4 m/s. When the wind blows from south with low speed (0–4 m/s), σ<sub>a</sub> is intermediate. The patterns of the wind dependence of σ<sub>a</sub> indicates that σ<sub>a</sub> is mainly dominated by local emissions. σ<sub>s</sub> displays a similar dependence on wind speed and direction to σ<sub>a</sub>, except in summer. In summer, the σ<sub>s</sub> value is highest when wind is from southeast with speed of 0–6 m/s. This indicates that the particle pollution resulting from regional transport is only significant in the summer season. ω also shows wind dependence to some extent though not as strong as σ<sub>a</sub> or σ<sub>s</sub>. Overall, the wind dependence results provide valuable information about the locations of aerosol pollution sources and suggest that the air pollution in summer is a regional problem but in other seasons it is mainly affected by local urban emissions.