Modified CaCO3@SMA nanoparticles obtained by coordination reaction between poly(styrene-co-maleicanhydride) (SMA) and calcium carbonate (CaCO3) nanoparticles were adopted as additive to preparepolyvinylidene fluoride (PVDF) flat membrane via thermally induced phase separation (TIPS) methodwith dioctyl phthalate (DOP) and dibutyl phthalate (DBP) as mixed diluent. The CaCO3 nanoparticlesmodified by SMA effectively reduced the adverse agglomeration of nanoparticles and made the additivedisperse evenly in PVDF matrix. The presence of modified CaCO3@SMA changed the membrane morphologyfrom dispersed spherulites with large pores to fuzzy dendrite structures with uniform pore sizes. Themembrane pore sizes, pore size distribution and tensile strength were significantly improved comparedto both virgin membranes and those containing unmodified CaCO3 nanoparticles. After the CaCO3 waspickled, the porosity and the connectivity between membrane pores were greatly enhanced, resultingin a significant increase in pure water flux. At the same time, the amphiphilic SMA fixed in and on themembrane surface improved the hydrophilic and anti-fouling properties demonstrated in a three-cycletest. The present study provided a potential TIPS method for the fabrication of PVDF membrane combinedwith a simple strategy of modified inorganic particle additive.