Atmospheric aerosol number concentration, atmospheric visibility and particulate mass concentrations, such as PM10, PM2.5 and PM1.0, were detected by an optical particle counter (OPC), a visibility meter and ambient particulate monitors respectively at the same time in Beijing during the winter of 2001. According to the analysis of multivariate linear regression for particulate mass concentration and visibility with atmospheric aerosol concentration, the empiric formulas are given for calculating the visibility, PM10, PM2.5 and PM1.0 from atmospheric aerosol number distribution measured by an OPC.