A modified expression is derived to calculate the steady-state rate of heterogeneous nucleation on an insoluble spherical particle. For the first time, this modified expression comprehensively considers three factors used in previous expressions, i.e., two mechanisms of cluster growth, the self-consistent expression for the equilibrium number density of clusters, and the effect of line tension. The effects of the three factors are analyzed, and the comparisons of predicted and measured critical supersaturations are presented to validate the advantage of the modified expression and investigate the contributions of the three factors to heterogeneous nucleation. The results show that all the three factors especially the line tension in previous expressions should be considered, which promote the heterogeneous nucleation process. It is also found that the predicted data of the modified expression are much closer to the experimental data than those of the previous expressions. (C) 2015 Elsevier Ltd. All rights reserved.