The hydrophobic ceramic membrane was prepared via surface modification, grafting by hexadecyltrimethoxysilane ( C16 ) molecules. Fourier transform infrared spectroscopy ( FT-IR ) confirmed the grafting of C16 molecules onto the ceramic membrane surface. The contact angle values of C16 modified alumina membrane was 158° by water contact angle measurements, which showed good hydrophobic character. This kind of modified alumina ceramic was applied in vacuum membrane distillation ( VMD) process of NaCl solutions. The higher permeate flux was achieved at flow rate 160 L/h,feed temperature of 70 ℃,vacuum of 0. 095 MPa. The VMD performance of hydrophobic alumina membrane under the optimal conditions was studied. During the 300 min operation process,the flux was about 20 kg/( m2 ·h) ,and the salt rejection could be stable at high values (>99. 9％) .