The invention discloses a technological preparation method of a bent LED lamp filament. The preparation method mainly comprises the following steps: etching a circuit on a metal substrate, using a machine to punch or cut a mosquito-repellent incense type vortex shaped structure, carrying out die bond, adhesive deposite and packaging on the lamp filament on the metal substrate, clamping two ends of the lamp filament with a fixture, and uniformly stretching the lamp filament outwards to manufacture the LED lamp filament. Based on the preparation method, the invention further discloses a bulb with the bent LED lamp filament. Compared with the lamp filament made of traditional ceramic, the lamp filament made of the metal or nonmetal substrate is higher in thermal conductivity and power; die bond is carried out on the front side and the reverse side of the metal or nonmetal substrate to enable luminescence of the front side and the reverse side of the LED lamp filament to be more uniform; the vortex shape enables luminescence of the lamp filament to be more three-dimensional and realizes low possibility of breakage of the lamp filament, and the yield of the bent LED lamp filament is higher; and the LED bulb prepared through the preparation technology disclosed by the invention is more uniform in luminescence, higher in wattage and longer in service life.