In anhydrous ethanol system, with methyltriethoxysilane (MTES) as raw material and sodium hydroxide as catalyst, through the reactions of hydrolysis and condensation, the hydrophobic polymethylsesquisiloxane nano-powders(PMQS) were synthetized.The chemical structure and surface morphology of PMQS were characterized by means of FTIR and SEM.The non-ionic surfactant was used to emulsify PMQS and ASO in order to obtain a translucent of PMQS /ASO microemulsion.Then the particle size of the emulsion micelles was measured by nano-particle surface potential analyzer.The application performance of ASO and PMQS/ASO emulsion was investigated.And the membrane surface morphology of cotton were studied through SEM.The results show that the property such as softness,slide and water proofing of cotton was much better when the quality ratio of PMQS:ASO was 3:7,.and with the particle size of the emulsion is about 150nm.While, the contact angle of cotton fabric is about 135 o.