Poly(vinylidene fluoride-co-hexafluoro propylene)(F26)-based asymmetry micro-porous membrane has been fabricated by a phase inversion process and applied in membrane distillation．Acetone (sweller)

N-methyl pyrrolidone (solvent) and polyethylene glycol 400 (additive) were used in casting solutions．Different effect of acetone and N-methyl pyrrolidone／acetone on membrane structure parameters was investigated and demonstrated by SEM．F26 microporous membrane with fingerlike and sponge structure was prepared in N-methyl pyrrolidone／acetone．F26 membrane prepared without any additives is superior to PVDF membrane by making a comparison of their contact angle to distilled water．The membrane distillation coeffcient of the experimental F26 membrane is higher than that of the experimental PVDF membrane

which can be ascribed to the special membrane structure of F26. Membrane distillation flux of F26 membranes was a little higber than that of the PVDF ones under the same operational conditions．