A hierarchical tree-like nanofiber membrane (TLNM) with high hydrophobicity was prepared via electrospinning polyvinylidene fluoride (PVDF) blended with tetrabutylammonium chloride (TBAC) and fluorinated acrylate copolymer (FA). Then, the hydrophobicity of PVDF/TBAC/FA TLNMs was further enhanced after ultrasonic treatment. The introduction of TBAC and FA promoted the formation of tree-like structures and the as-prepared PVDF/TBAC/FA TLNMs showed strong hydrophobicity with a water contact angle of 137 +/- 3 degrees, extremely small pore size of 0.21-0.26 mu m, outstanding mechanical strength of 7.90 MPa and high liquid entry pressure of 0.23 MPa, making the membrane possess excellent performance in the direct contact membrane distillation (DCMD) process. The PVDF/TBAC/3% FA TLNMs with a thickness of 60 +/- 3 mu m showed a superior permeate flux of 54.39 L/m(2) h and the salt rejection rate kept above 99.5% after 9 h using a 3.5 wt% NaCl as the feed solution while with the feed and permeate temperatures were set as 60 degrees C and 20 degrees C, respectively. This work highlights the promising application of this TLNMs in the field of membrane distillation.