Organic silicone microcapsule powder water repellent was prepared through film forming microcapsule technology and spray drying technology. Performance of organic silicone powder water repellent was evaluated in terms of relative surface oil content, productive rate, mean particle size, morphology, waterproof property, anti penetrability property and influence on compressive strength and shrinkage rate of cement based materials. The effect of organic silicone microcapsule powder water repellents was superior to that of liquid polydimethylsiloxane（PDMs）. With 3% content（by mass） of octyl triethoxy silane substituting for PDMs, core material of organic silicone water repellent was optimized, the water absorption rate of mortar after soaking for 48h decreased to 3%4%, impermeability pressure increased by 489%, and shrinkage rate decreased by 68% at 90d loading age. It is indicated from SEM analysis that organic silicone microcapsule powder water repellent is of core shell structure, with active organic silicone core materials and nano calcium carbonate fillers wrapped with polyvinyl alcohol and distributed inside. After hydrolysis, water soluble polyvinyl alcohol is dissolved, and active organic silicone core material was gradually released, which participated in the formation of organic silicone hydrophobic membrane and made effects for waterproofing, and for the improvement of hydration degree and structure compactness.