In order to prepare guar gum (GG) nanofibers with diameter less than 100nm and solve the problem of difficulty in electrospinning. cetyl dimethyl ethyl ammonium bromide (EHDAB) was used as surfactant, Calcium chloride (CaCl2) was used as a strong electrolyte, and GG nanofibers were prepared by electrospinning. The effects of EHDAB and CaCl2 mass fractions on the surface tension, electrical conductivity and viscosity of the spinning solution were investigated; the morphology, water contact angle, mechanical properties and antibacterial properties of the nanofibers were characterized. The results show that solution conductivity, electric field force, and spinning efficiency can be significantly increased by CaCl2; When adding mass fraction of EHDAB and CaCl2, the surface tension and viscosity fall down. Especially, the mass fraction of GG/EHDAB/CaCl2 was 0.9:0.2:0%, and the minimum average diameter was 40nm. The minimum water contact angle of GG ultrafine nanofiber membrane is 23°, and it has good hydrophilicity and antibacterial properties.