As the rapid development of mobile phone shell and lights, the market demand of high quality polishing liquid was increased, and the important composition of polishing fluid  is  big  particle size silica sol. The current domestic large diameter silicon sol products  is  not relatively stable, the import share is larger, and the price is higher. The large size, good performance and high concentration silica sol were introduced, the preparation of the crystal seed of the large diameter high concentration silica sol,the particle growth mechanism , the influencing factors of particle growth, the stability of the particle size, the influencing of factors of the stability and enrichment mechanism were systematically analyzed.