We build a novel system that utilizes an aerodynamic aerosol classifier (AAC) combined with a single-particle aerosol mass spectrometry (SPAMS) to simultaneously characterize the volume equivalent diameter (D_ve), chemical compositions, and effective density (ρ_e) of individual particles in real time. A test of the AAC-SPAMS with both spherical and aspherical particles shows that the deviations between the measured and theoretical values are less than 6 %.