The invention discloses a preparation method of a PBO composite ultra-high temperature filter material, which comprises the following steps that: a plain blanket is formed through an acupuncture and spunlaced composite process, and then soaked in chemical solvent to prepare the ultra-high temperature filter material, the dust facing surface in the prepared filter material comprises PBO and basalt fibers which are blended, wherein the weight proportion of the PBO fibers is 10 to 15 percent; base cloth comprises PBO long filaments and basalt filaments which are interwoven; and a bottom layer adopts 100 percent basalt fibers. The preparation method of the PBO composite ultra-high temperature filter material effectively reduces the damage of the fibers, improves the strong force of the filter material, meets the need of ultra high temperature flue gas treatment, and is applicable to a bag-type dust collector for ultra high temperature flue gas treatment at above 500DEG C.