We present theoretical analysis of the role of the radiation absorption asymmetry factor J1 in photophoresis of aerosol particles. The efficiency of applying the mentioned microphysical optical characteristic in predicting direction and magnitude of the photophoretic force and velocity is demonstrated. Based on the Mie theory, within the framework of optically homogeneous spherical particle model, the J1 values for weakly, moderately, and strongly absorbing model particles are calculated. The J1 dependences on size parameter and incident radiation wavelength are considered. The known asymptotic results for J1 obtained for the Rayleigh limit and for the limit of ray optics are analyzed. Further investigations of the asymmetry factor properties for the model of two-layer particles taking into account the spectral distribution of incident radiation are considered.