Abstract:  The traditional soymilk\|making method costs a relatively long time， and the protein of soy milk made from soybean without soaking was low in content and hard to absorb. The development of soaking\|free soybean can solve these problems. To get high quality soaking\|free soybean， the pretreatment process of soybean and the effects of soaking time， temperature and solution concentration on the protein content and stability of soy milk and the aerobic plate count of soybean were studied. Single\|factor experiments and orthogonal experiment were carried on and the results were analyzed by multi\|index integrated assessment method. It was shown that ClO2 solution was the best choice for soybean pre\|cleaning， and NaHCO3 was the best choice for soaking. Soaking time， temperature and solution concentration all had significant influence on the integrated assessment. The best soaking process conditions were as follows: soaking time 12 h， soaking temperature 15℃ and NaHCO3 solution concentration 05%. Under the optimal conditions， the logarithmic aerobic plate count of soybean was 471， the protein content was up to 268 g·100 mL-1， and the stability of soy milk was 0786.

Key words: soaking\, free soybean, soy milk, soaking process, protein, stability, aerobic plate count