Objective: To investigate rationality of vacuum-assisted extraction (VAE) technology for Carthami Flos and optimize its extraction conditions. Method: Response surface methodology was used to optimize VAE technology of Carthami Flos with yield of hydroxy safflower yellow A as index

its major factors were boiling temperature

ethanol concentration

extraction time and cycles

which had influence on yield of hydroxy safflower yellow A were tested by an Box-Behnken design.Besides

micro-morphology of plant materials were observed by scanning electron microscope (SEM). Result: Optimum extraction conditions were as follows:extracted twice with 20 times the amount of 50% ethanol at 65℃

extraction time of 42 min for per time.Under these conditions

yield of hydroxy safflower yellow A reached 1.51%. Conclusion: Compared with conventional heat reflux extraction

VAE has higher extraction efficiency.VAE is an efficient and simple method for extracting hydroxy safflower yellow A from Carthami Flos

which shows great potential for becoming an alternative technique for extraction of heat sensitive compounds from traditional Chinese medicine.