A functional POSS monomer (POSS-NH2) was employed to modify cyanate ester (CE) resin. A series of POSS-NH2/CE hybrids containing different content of POSS have been prepared by melt casting and then curing. The curing kinetics and reaction mechanisms of the resin systems were studied by using FT-IR. Dielectric properties of the hybrids were also investigated. FT-IR results show that both temperature and POSS content may influence the curing reaction of CE. POSS-NH2 mainly displays the catalytic effect at higher temperature (220oC). The circumstance is more complex at lower temperature(190oC). CE1 containing 1 wt% of POSS has the best dielectric properties.