Highly constrained by the requirements of high porosity and micropore sizes, during long term operations, the traditional single -bore hollow fiber membranes have several problems; among them, the easy breakage and performance instability. In this work, Tri Bore Hollow Fiber (TBHF) membrane with triangle outer geometry was designed and successfully fabricated via the specially designed spinneret and optimized spinning conditions. TBF module is also prepared and manufactured in the easiest way possible. Besides, the TBF membranes exhibited superior stability in terms of vapor permeation flux and salt rejection during the MD experiment with robust operational conditions.