Preparation method of glabrous sarcandra herb injection

The invention discloses a preparation method of a glabrous sarcandra herb injection. The preparation method comprises the following steps: taking 5,000-10,000g of glabrous sarcandra herb, adding water, extracting 2-3 times, merging extract liquids, filtering, concentrating the filtrate until the relative density is 1.25-1.40 at 70 DEG C; adding ethanol to precipitate until the ethanol content is 60%-90%; refrigerating for 24-72 hours, filtering, recovering ethanol from the filtrate and concentrating until each ml of filtrate contains 5-15g of raw medicine; adjusting the pH value to 3-5, heating to 0.5-2.0 hours, refrigerating for 12-48 hours, filtering, adjusting the pH value of the filtrate to 5-7, and heating until the content ratio of chlorogenic acid to cryptochlorogenic acid in the filtrate is (3:1) to (3:2); adding a proper amount of activated carbon, filtering, adding injection water to the filtrate, and diluting into 1,000ml; and filtering, adding 3-10ml of polysorbate 80, stirring evenly, adjusting the pH value to 5.5-7.0, filtering, filling and sterilizing to obtain the glabrous sarcandra herb injection.