The invention discloses a preparation method of a microwave sulfur lamp bulb, which relates to a preparation method of a sulfur lamp bulb. It solves the problem that the existing preparation process cannot guarantee a high vacuum in the bulb, and the purity of the sulfur powder and the filling amount of sulfur and Ar gas are not easy to control, so that the luminous brightness, efficiency, color rendering and The problem of low service life. The preparation method of the present invention is as follows: 1. preparation device; 2. heating and vacuuming, so that the vacuum degree in the device is maintained at 2~8×10-4Pa; 3. cracking the protruding glass tip above the glass container; 4. Use a muffle furnace to heat the sulfur powder in the glass container, so that the sulfur powder in the glass container evaporates into the quartz bulb; 5. After the sulfur powder is completely evaporated, cool to room temperature, then vacuumize the bulb and fill it with Ar gas , that is, to produce a microwave sulfur lamp bulb. The luminescence spectrum of the light bulb prepared by the invention is close to the solar spectrum, and the color rendering index reaches 82, and the service life of the light bulb is significantly improved due to the high vacuum degree and high-purity sulfur in the light bulb.