Polysiloxanes and copolysiloxanes bearing pendant long alkyl ether groups were synthesized by the hydrosilylation of PHMS with allylalkyl ethers. Their phase transition properties were studied. Drug release properties of the blended rubber films consisted of PDMS and polysiloxanes or copolysiloxanes obtained were also investigated. The melting temperature of polysiloxanes or copolysiloxanes increase as the lengthening of the pendant alkyl groups or the increasing of the content of longer alkyl groups. X-ray diffraction showed that the pendant alkyl groups possess lateral order arrangement.The effect of temperature on the permeation rate of the drug Levonorgestrel (LNG)through the blended films with different polysiloxanes or copolysiloxanes were studied.The permeation rate of the drugs increase as the increasing of temperature and are accelerated as the phase transition from crystalline to isotropic.