In the present work, the TIPS behavior of isotactic polypropylene (iPP)/di-n-butyl phthalate (DBP)/dioctyl phthalate (DOP)/nano-SiO2 system and the competition relation between liquid-liquid phase separation and polymer crystal lization are successfully adjusted by adding nano-SiO2. The liquid-liquid phase separation temperature of the system increases with increasing nano-SiO2 content. Besides, iPP crystallization temperature is also changed after adding nano-SiO2. [PP/nano-SiO2 blend hollow fiber microporous membrane is prepared via TIPS method. SEM photos show that the membrane exhibits mixed morphology combining cellular structure relating to liquid-liquid phase separation and branch structure originating from polymer crystallization. The relative weight of cellular structure first decreases and then increases with the increase of nano-SiO(2 )content. Furthermore, porosity, connectivity among pores and pure water flux of the membrane first increase and then decrease with increasing nano-SiO2 content. However, mechanical performance of the membrane is improved at all times with increasing nano-SiO2 content. (C) 2018 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.