Objective:To study preparation and optimum conditions in the extraction and purifying of Rukang Capsules.Methods:The amount of water

extracting time and extracting times were optimized based on the contents of Astragaloside

in water extracting process

and also for the effects of alcohol concentration

decoction concentration and sedimentary time on removing residue.Results:The optimum condition of Rukang Capsules for water extraction were 12 times of water

2 times and 2 h each times;75% alcohol

1∶1.5 decoction should be used for purifying process with in 24 h.Conclusion:The optimum condition was reasonable and practice for industrial production.