Drop multimode breakup is more complex than the bag and shear breakup regimes, and modeling drop breakup in the multimode breakup regime is less reported. In this article, a theoretical model is developed to predict the drop breakup properties in the multimode regime in a more accurate manner. In the present model, the process of the drop deformation and breakup are regarded as the movement of the center of the mass along the cross-stream and streamwise directions, respectively. The displacement of the center of the mass is obtained by solving a pressure balance equation and a mechanical analog model equation. Drop breakup occurs when the displacement of the mass center is out of the scale defined by the threshold function of Weber number. The characteristics of the proposed model as well as the breakup properties of the drops in the multimode regime are addressed by comparing the predicted results with the experimental data in the open published literature.