The process conditions of ultrasonic-assisted alkali extraction method of insoluble dietary fiber were optimized by using the Aronia prunifolia ‘Viking’ pomace as raw materials.The influence of sodium hydroxide mass fraction，action time and ultrasonic power on Insoluble Dietary Fiber extraction rate from Aronia prunifolia ‘Viking’ Pomace(APIDF) was studied.And the extraction process of APIDF was optimized by response surface analysis method with three-factors and three-levels.The results showed that the optimal extraction conditions of APIDF were as follows：sodium hydroxide mass fraction 1%，sodium hydroxide temperature 42 ℃，and ultrasonic power 225 W.Under the above conditions，the APIDF extraction rate was 35.47%，and its purity reached 90.04%(mass fraction).