Put the medicinal herbs into the extraction tank and add solvents such as water, ethanol, methanol, acetone, etc. (according to the process requirements). Turn on the heating system of the extraction tank, heat the extraction solution to boiling for about half an hour, and then use a filter tube to draw in one-third of the extraction solution. Close the extraction tank and jacket hot water, turn on the concentration tank and heating system to maintain the temperature of the concentrated juice at around 80 ℃, and keep the vacuum degree at -0.05 to -0.09MPA, The secondary steam generated during concentration passes through the condenser and cooler to become a condensate and flows back to the extraction tank as a new solvent to be added to the medicine. The new solvent passes through the medicinal layer from top to bottom and reaches the bottom of the extraction tank. The soluble components in the medicinal materials dissolve in the solvent in the extraction tank. The extraction liquid is drawn into the concentration tank through a filter tube, and the secondary steam generated during concentration is sent to the extraction tank as a new solvent to form a new solvent reflux extraction. The concentration continues until it is dissolved (the extraction liquid is colorless) and concentrated into the required specific gravity ointment. The colorless liquid in the extraction tank can be reused next time. If organic solvent extraction is used, add an appropriate amount of water first, open the pipeline and jacket hot water, recover the solvent, and then discharge the residue.