Abstract: Effect of seeding on industrial batch crystallization of sodium fluosilicate was introduced.Six groups of opitimization tests were carried out and recorded in detail according to whether adding seed crystal or not and the feeding modes of acid and salt.A number of different crystalline samples from the six reaction modes were analyzed via XRD and TEM and opitimized amount of seeding was found.Research results showed that the good quality product could be prepared and meet the requirement of different customers through the optimized batch crystallization of sodium fluosilicate.A sand-like sodium fluosilicate product could be produced by the semi-continuous method i.e.by seeding and adding acid and salt simultaneously and proportionally.