Comb-like polysiloxanes with polyhedral oligomeric silsesquioxane (POSS) and oligo(ethylene oxide) groups (EO) in the side chains were prepared through the hydrosilylation reaction of poly(ethylhydrosiloxane) (PEHS) with 1-allyl-3,5,7,9,11,13,15-heptacyclopentylpentacyclo-[$9.5.1.1^{3,9}.1^{5,15}.1^{7,13}$] octasiloxane (allyl-CyPOSS) and allyl-functionalized oligo(ethylene glycol) monomethyl ethers. The physical and chemical properties of these polysiloxanes were studied systematically by changing the content of bulky POSS groups and hydrophilic flexible oligo(ethylene oxide) groups with different lengths. For example, the glass transition temperature of the polymer increased with increasing content of POSS side groups, whereas the melting temperature and heat of fusion of the oligo(ethylene oxide) side group decreases. Furthermore, the glass transition temperature and melting temperature increase when the length of the EO group was increased, whereas the decomposition temperature decreased.