Liquid crystalline(LC) polysiloxane with cholesteric group in side chain has been prepared by a polyhydrosilylation reaction of poly(hydrogenmethylsiloxane) with a terminal alkenic cholesteric group. The structure of these polymers were confirmed by analysis of IR and NMR. Its phase transfomation was studied by optical microscope and DSC. The results showed that the polymers form a LC phase in certain temperature range

and the temperature range depends not only on the flexibility of the flexible spacer

but also the content of cholesteric side chain uni-ts. Therefore the temperature range fo LC phase can be controlled by changing the content of the cholesteric side chain units and the structure of the flexible spacer.