In order to improve the mechanical properties, siloxane oligomers or polymers with functionalized end groups are of ien copolymerized with organic monomers to induce linkages such as urea, amide, urethane, and imide, etc. In this study, the aminopropyl-terminated poly(1,1,1-trifluoropropylmethyl-dimethyl)siloxane were bulk-polymerized with 1,) -bis(Y- aminopropyl) telramethyl disiloxane(DSX) as an end blocker, oclamethylcyclotelrasiloxane(D4), and (1,1,1-trifluoropropyl) methylcyclopolysiloxane (F)4, and a basic catalyst. Their compositions and molecular weights were analyzed by 1H-NMR spectroscopy, and the potentiometric titration method was used for the confirmation of molecular weight. The compositions of the polymers were found to be almost equal to the feed ratios. It was realized that well-defied siloxane oligomers having controlled composition and molecular weight could be utilized in synthesis and properties control of siloxane-organic copolymers.