For the purpose of application of theoretical calculation to practical vacuum preloading projects and providing guidance in practical application, an equation for soft ground consolidation in the radial direction under vacuum preloading was established by assuming that the vacuum degree attenuated linearly, and formulas for the excess pore pressure and degree of consolidation were developed. Based on study of the effects of the permeability coefficient in smear zones, analytical solutions for the average pore pressure and degree of consolidation were deduced and verified with a constant permeability coefficient and linearly changing permeability coefficient, respectively. Results of analysis show that the smaller the vacuum degree attenuation coefficients, k₁ and k₂, the well resistance factor, n, and the radius ratio of the smear zone to drainage system, s, and the closer the ratio of the permeability coefficients of the undisturbed zone to the smear zone, α, to s, the better the effect of vacuum preloading. The analytical solutions considering the linear attenuation of the vacuum degree and Hansbos solutions were compared with field observations of the degree of consolidation of the foundation under vacuum preloading at the Jiaxing Port. Results show that the analytical solutions are more consistent with field observations, and the solutions considering the linear change of the permeability coefficient in smear zones correspond better with engineering practices.