Slot electrospinning that uses narrow slot as a spinneret combines the advantages of both needle and needleless electrospinning with precisely controlled solution condition. Most of the existing slot electrospinning techniques, however, use a straight linear slot as spinneret. The effects of slot geometry on electrospinning process and fiber morphology have not been reported in the research literature. In this study, four convex slots with different line shapes, i.e., curved, straight, rectangle and triangle, have been used as spinnerets to examine the effects of slot line shape on electrospinning process, fiber morphology and productivity. The electric field intensity distribution of these slot spinnerets was analyzed by finite element method. Our experimental results have indicated that the slot line shape played an important role in affecting fiber diameter, productivity and uniformity of the fibrous membranes. Compared to the other slots studied, the curved slot can produce nanofibers with larger productivity and the resulting fibrous membranes were more uniform as well; the curved slot had higher electric field with more uniform distribution of electric field intensity along the slot length direction. These understandings may be helpful for designing new slot electrospinning systems.