Zeolite A is a crystalline aluminosilicate that synthesized hydrothermally. Several reaction engineering models developed for precipitation of this zeolite. Three reaction engineering models were presented by Thompson based on gel consumption and conversion to zeolite. This paper simulated batch reaction engineering of zeolite A utilizing Thompson’s second and third models. The results of these models were compared to eachother and satisfied with Kerr’s laboratory data. Modelling results showed the gradient of gel conversion was decreased during nucleation stage but it was approximately constant during crystallization. AlsoThomson’ssecond model showed a better fitnesswith experimental data rather than Thompson’sthird model.