Flow property of particles is one key factor in influencing the co-utilization of biomass and coal in an entrained flow gasifier. In this paper, the flow properties of the blended particles of rice straw and coal were systematically studied. The results showed that Hausner ratio cannot indicate flow ability of the blends because of the particle segregation during shaking. Both the tangent of the angle of internal friction and a (the mean value of the angle of internal friction and angle of repose) of the blends display a linear increase with the mass fraction of rice straw, and their increments are almost the same. Moreover, the influence of particle shape of rice straw particles on both two kinds of angles was also found by introducing an orientation revision parameter, and the detailed expressions were also obtained. (C) 2012 Elsevier Ltd. All rights reserved.