SiO2-TiO2 systems were extensively investigated in sol-gel process to fabricate passive optical planar waveguides, channel waveguides, interference filters and weather resistant optical memory discs. A high quality, crack free optical thick layer and low processing cost are key success factor for optical applications. Two formulated SiO2-TiO2 systems with 1% and 10% TiO2 were deposited on 20mm x 20mm Si-wafer using multi-spin coating process was investigated on refractive index (n), build-up layer until crack appeared on film. The structure analysis of multi spin was investigated using FTIR. The value of refractive index (n) and thickness of thin films (d) were taken every deposited layer using spectroscopic reflectance and surface morphology of crack thick film by FESEM. SiO2-TiO2 thin film appeared peak ~950cm-1 associated with the Si-O stretching vibrations of Si-OH and Si-O-Ti groups by multi spin coating processes. SiO2-TiO2 system with 10% TiO2 in siloxane structure was found capable on building thick layer up to 2.4 μm at 17 time cycles spins and heat treatments at 680 oC. The value of n was reduced with increasing of number of cycles and believes to form nanoporous zones between interfacial layers during hydrolysis and condensation process of each layer by multi spin coating process.