Abstract: To deal with the singularity in Poisson-Boltzmann models, which is caused by fixed charge distribution in biomolecules, several decomposition schemes have been proposed in literatures. In this paper, three commonly-used decomposition schemes for Poisson-Boltzmann models are reviewed and compared. That is, a two-term decomposition scheme, a three-term decomposition in biomolecular domain only, and a three-term decomposition in the whole domain. Numerical tests on a Born ball model with analytical solution show the performance of each scheme.