目的：为煎煮药物投放加水量寻找一种更简便、快捷、合理的方法。方法：选择５０张不同的处方，在经验加水的基础上，观察加水量和得药量的关系，求出平均吸水系数（Ｋ）；再选择５０张不同的处方，根据平均吸水系数（Ｋ）算出加水量。结果：平均误差率为７．１８％。结论：避免加水量的盲目性，保证了药物的煎煮质量。 Objective: To find a simpler, quicker, and more reasonable method for adding water to decoction. Method: Select 50 different prescriptions, observe the relationship between the amount of water added and the amount of drug obtained on the basis of experience of adding water, and find the average coefficient of absorption (K); then select 50 different prescriptions according to the average coefficient of absorption (K) Calculate the amount of water added. Results: The average error rate was 7.18%. Conclusion: Avoid the blindness of the amount of water and ensure the decoction quality of the drug.