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A series of high-adhesion copoly(imide siloxane)(PIS) copolymers were prepared with fluorine dianhydride 4,4-(hexafluoroisopropylidene)diphthalic anhydride(6FDA) and two kinds of functional diamine,2,2-bis(trifluoromethyl)-[1, 1-biphenyl]-4,4-diamine(TFMB) and 1,3-Bis(3-aminopropyl) tetramethyl disiloxane (GAPD) via a conventional two-stage process with thermal imidization.The soft and hard segment in the copolymer is composed of 6FDA-GAPD and 6FDA-TFMB,respectively.The structure of the polyimide was characterized by fourier transformer infrared (FT-IR).Mechanical,thermal,optical,and hydrophobic properties of those copoly(imide siloxane) copolymers have been evaluated with respect to siloxane loading kept to 5%,10%, 15%,20%(n(TFMB)∶n(GAPD)).The properties of the random copolymers were compared with the homopolyimide synthesized without siloxane moiety.The thermal properties and mechanical properties of the resulting PIS decreased with the increase in siloxane loading, such as,the 5wt% thermal decomposition temperature(T5%) and the 10wt% thermal decomposition temperatureand(T10%) decreased from 537 ℃ to 486℃,and 558℃ to 506℃, the tensile strength decreased from 83.4MPa to 44.6MPa respectively, demonstrating that PIs films still possessed a good thermal properties.The resulting PIS also shows a good adhesion and excellent optical transparency in the UV-visible range and other fantastic properties,such as outstanding hydrophobic properties, prominent solubility in common organic solvents.The introduction of siloxane segments dramatically improve the adhesion of PI films in the low content(0~1 0%), and decrease significantly with the increase of the content(10~20%), while all exhibited a better adhesion values than homopolyimide.Due to the addition of-CF3 and siloxane moiety, the solubility of PI films is greatly enhanced, it is able to dissolved in polar aprotic solvents,such as DMAC,DMF, NMP, and contact angle,surface energy and water absorption were also measured.