Treatment of waste drilling slurries has become one of the important problems encountered in urban construction. The application of pressure filtration technology brings significant advantages in slurries treatment. In order to give a better insight into the mechanism of pressure filtration, a model was introduced to analyze the relationship between filtration pressure, time and treatment results. The proposed model was validated using existing data. The parametric studies of the model show that the increase of the filtration pressure can reduce the filtration time and the permeability coefficient of the filter cake, While filtration time decreases very slowly beyond a certain extent. In addition, the relationship among filtration pressure, time and treatment results is further validated by test results.