The constant temperature soaking, low pressure cooking and air drying were used to pre-cook the kidney beans in order to make the kidney beans get maturity simultaneously when cooked with rice. The temperature of constant temperature soaking, the pressure and the time of low pressure cooking was taken as the independent variable, and gelatinization degree was taken as the response value to get the optimal process condition through the experiments. The results showed that the optimum processing conditions for kidney beans were as followed: soaking temperature 50 ℃, cooking pressure 50 kPa, the time of low pressure cooking 5 min. The gelatinization degree of kidney beans is 70.50%. Under the above-mentioned conditions, the kidney beans' surface is complete and its moisture content was 7%. The pre-cooked kidney beans can get maturity when cooked with rice.