The aim of this study was to establish a model of precipitation for strontium molybdate precipitate. From the parameters study, a mechanism of Brownian and laminar agglomeration with nucleation, growth and agglomeration is proposed for the bipyramidal population. A model of agglomeration coupled with nucleation and growth with two fitted parameters only was developed in order to predict the morphologies of the hierarchical agglomerates with respect to experimental conditions [CAM07]