The two-layer ZrO2/SiO2 and SiO2/ZrO2 thin films were deposited on K9 glass by sol-gel dip coating method, and the infiltrating between this two types of films was explored. X-ray photoelectron spectroscopy (XPS) was used to measure the variation of composition in different thickness of film, and ellipometry was used to fit the experimental result of the XPS. According to the experimental results of the XPS, the ellipsometric model was coustructed. The results showed that the ellipsometric curve of simulated results accorded with that measured by ellipsometry very well. The infiltrating between the two-layer ZrO2/SiO2 film was not serious and the variation of film composition in interface was very obvious; at a given thickness, the film′s composition no longer changed; On the contrary ,the infiltrating between two-layer SiO2/ZrO2 film was very serious and infiltrative layer is very thick, and the complete infiltrating almost happened in the bottom layer.