The invention discloses an alumina fiber-bismuth oxide compound catalyst preparation method which comprises the steps: (1) adding aluminum salt into polyvinyl alcohol and absolute ethyl alcohol mixedliquor with a volume ratio of 1 to (1 to 3), stirring for 1 to 2 h, then injecting into an electrostatic spinning device, performing electrostatic spinning under the conditions that voltage is 15 to 25 kV, the receiving distance is 5 to 15 cm, and the receiving time is 2 to 5 h, putting an obtained spinning material into a muffle furnace for being heated and dried, warming to 400 to 500 DEG C according to a heating rate of 5 to 10 DEG C and keeping constant temperature for 5 to 8 h to obtain alumina fiber; (2) adding water-soluble bismuth salt into a water solution containing urea, stirring for 3 to 8 h under the condition of 90 to 105 DEG C, the adding the alumina fiber, continuing stirring for 15 to 25 min, sealing, putting into a 150 to 200 DEG C oven to be heated for 8 to 12 h, cooling, respectively utilizing deionized water and absolute ethyl alcohol to wash 2 to 5 times and drying to obtain an alumina fiber-bismuth oxide compound catalyst. The alumina fiber-bismuth oxide compoundcatalyst prepared by the preparation method disclosed by the invention has the characteristics of high specific surface area, good thermal stability and excellent catalytic performance.