Abstract: The styrene, divinylbenzene and KH570 were used as monomers to preparer the cross-link polystyrene microspheres (SiO₂/polystyrene hydrophobic composite microspheres), on which the SiO₂ rough structure was sucessfully designed via suspension polymerization along with sol-gel reaction in one step. Besides, effects of the oil phase composition, amount of the KH570 and the sol-gel reaction condition on the strength and hydrophobic properties of the SiO₂/polystyrene hydrophobic composite microspheres were studied. The results show that the SiO₂/polystyrene hydrophobic composite microspheres with durable hydrophobic properties, high strength and ultra-low density could be obtained when the toluene in the oil phase is discarded and the pH value of the system is tuned to 10-11 by ammonia-water at the 50°C reaction stage. The SiO₂/polystyrene hydrophobic composite microsphere exhibits the apparent density about 0.9917 g∙cm⁻³, low crushing rate (2.53% under 69 MPa closure pressure), high initial static water contact angle (as high as 140.7°) and excellent heat resistance (the glass transition temperature and decomposition temperature are up to 160°C and 390°C, respectively). When refluxed in the chelate acid HD and FA that applied in Well A5 in Weizhou X Oil field for 30 days, the static water contact angles on the surface of the SiO₂/polystyrene hydrophobic composite microspheres fluctuate only within ±10% and ±7%, respectively. The SiO₂/polystyrene hydrophobic composite microsphere shows great potential in deep reservoir as a proppant, which is also suitable for the water control process as a packing material.