Abstract: In order to extract acid soluble collagen( ASC) from the foot of defective Haliotis discus,the process conditions of single- stage dynamic intermittent extraction and multi- stage dynamic continuous countercurrent extraction were investigated and compared. The results showed that the optimum conditions for single- stage dynamic extraction were as follows: acetic acid( 1 mol / L) / hydrochloric acid( 0.4 mol / L) 50%( v / v),solid to liquid ratio 1 ∶ 10,flow rate 40 m L / min,extraction time 1 h and extraction times 2. Under these conditions,the ASC extraction rate and ASC concentration reached a highest value of 11.2% and 1.04 mg / m L,respectively.Moreover,it was found that three- stages was the best condition for dynamic continuous countercurrent extraction and obtained a higher ASC extraction rate( 16.9%) and ASC concentration( 3.12 mg / m L). Based on these results,ASC was further purified by regulating ammonium sulfate concentration and p H value simultaneously. The highest ASC recovery ratio( 89.1%) and ASC purity( 88.4%) were obtained when ammonium sulfate concentration and p H value were controlled at 0.4 mol / L and 5.6,respectively.