Membrane gas-liquid separation technology has been widely employed in membrane filtration, distillation, and gas absorption, attributed to its high mass transfer efficiency. However, hydrophobic membranes may suffer from pore wetting at low operational pressure difference, leading to the deterioration of removal flux. Hence, anti-wetting strategy via membrane surface modification to improve its intrinsic hydrophobicity needs to be investigated. In this work, modified superhydrophobic polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) membrane was synthesized via non-solvent induced phase separation. Polydimethylsilane-grafted-silica (PGS) nanoparticles with non-polar Si-O-Si bonds were used as surface modifier in coagulation bath to enhance membrane surface hydrophobicity. Results demonstrated that the addition of nanoparticles improved the surface roughness via formation of hierarchical structure. Additionally, the deposition of nanoparticles on polymer spherulites significantly reduced the surface free energy. As a result, modified membranes achieved superhydrophobicity with water contact angle exceeding 150o. The stability tests also showed that the deposition layer of modified membrane was mechanically and thermally robust. This superhydrophobic modification by PGS nanoparticles is an advanced and facile approach to alleviate membrane wetting.