We describe the synthesis and characteristics of the water-soluble network polymers consisting of POSS. When [ClH3N(CH2)(3)](8)Si8O12 and [HO2C(CH2)(2)CONH(CH2)(3)](8)Si8O12 were condensed in the aqueous solutions, a series of the POSS polymers with the different cross-linking ratios between POSS can be synthesized by changing the monomer concentrations in the reaction Solutions. The hydrophobicity inside the POSS polymers and the mobility of the entrapped molecules into the polymers significantly depend on the cross-linking ratio of the polymers. The refractive indices of the thin films obtained from the aqueous Solutions of the polymer were examined, and it was revealed that the decrease of the cross-linking ratio can significantly lift LIP the refractive indices from 1.51 to 1.58 due to the effect of the different amount of polar Substitution groups Such as amino and carboxylate groups, We demonstrate one example for modulating the properties of the POSS-based material via the small conditional change in the synthesis.