Theasymmetric hydrosilylation of poly (isopropenyl methyl ketone) gave an optically active polymer of poly (3-methyl-3-butene-2-ol). The reaction was car-ried out with diphenyl silane and a rhodiun (Ⅰ) catalyst containing a chiral thiazolidine ligand of 2-(2-pyridyl)-4-carbomethoxy-1, 3-thizolidine (A). The effect of reaction conditions on the optical rotation of the polymer products was studied in detail. The highest specfic rotation ([a]20/D) was+19.8° when the hydrosilylation was carried out in 1, 4-diixane at room temperature. On the other hand, the copolymer for n (isopropenyl methyl ketone)/n (stylrene)=1 is the corres ponding alcohol having negative s maller specific rotation,-5.4°.