The invention discloses a medicament for treating gonarthromeningitis, which is prepared from the following raw materials in portion by weight: 1,500 to 1,800 portions of radix astragali, 600 to 950 portions of largeleaf gentian root, 500 to 650 portions of Chinese angelica, 500 to 650 portions of himalayan teasel root, 500 to 650 portions of tree peony bark, 500 to 650 portions of Chinese thorowax root, 600 to 950 portions of turmeric, 500 to 650 portions of Chinese taxillus twig, 600 to 950 portions of rhizoma dioscoreae septemlobae, 300 to 500 portions of medicinal cyathula root, 300 to 500 portions of raw licorice, 100 to 120 portions of dextrin, 1.5 to 2.0 portions of aspartame, 2.5 to 3.0 portions of milk flavor, and 4.5 to 5.5 portions of mint essence. Preparation technology comprises the steps of: adding 10 times of water into the components to decoct for 3 times, merging and filtering decoction solutions, condensing a filtrate until the relative density is between 1.18 and 1.22 (80 DEG C), adding ethanol into the filtrate when the filtrate is cooled to 40 DEG C to ensure that the ethanol content reaches 50 percent, fully stirring the obtained solution, standing the obtained solution, and filtering to obtain a supernatant fluid; and adding 50 percent ethanol which is one half of a first ethanol precipitation solution into residue, stirring the obtained solution evenly, standing the solution, filtering the solution, merging ethanol solutions, recovering the ethanol, condensing the solution until the relative density is between 1.08 and 1.14 (65 DEG C), adding the dextrin and the aspartame into the solution to mix evenly, performing spray drying to obtain dry extract powder, and adding the milk flavor and the mint essence into the dry extract powder to mix evenly to obtain particles. The medicament is used for treating diseases such as knee joint swelling, pain and function restriction caused by the gonarthromeningitis, and has the functions of benefiting qi.