To enhance the mechanical properties and wetting resistance of poly(vinylidene fluoride) (PVDF) membranes for membrane distillation (MD) of seawater, we have added n-butylamine modified graphene oxide (GO-NBA) in PVDF flat-sheet and hollow fiber membranes. For the first time, it is found that the addition of GO-NBA leads to PVDF flat sheet membranes with greater mechanical properties than that of conventional GO because of better compatibility, dispersity and crystalline structure. The addition of the GO-NBA also improves the mechanical properties of PVDF hollow fiber membranes in both tensile and hoop directions. With a small loading of 0.5 wt% GO-NBA in PVDF hollow fiber membranes, the maximum tensile stress, maximum tensile stain and Young's modulus increase by 32%, 63% and 71%, respectively, while the liquid entry pressure (LEP) and burst pressure jump by 67% and 15%, respectively. Under direct contact membrane distillation (DCMD), the 0.5 wt% GO-NBA incorporated membrane shows a flux of 61.9 kg m(-2) h(-1) and a salt rejection of 99.9% using a model seawater as the feed at 80 degrees C. This work might provide useful insights to fabricate robust MD membranes for seawater desalination.