The invention discloses a preparation method of a Chinese medicine irrigation solution for treating constipation type trichomonas vaginitis, belonging to the technical field of preparation method of Chinese medicines. At present, generally, antibiotics and sulfanilamide medicines are used for treating constipation type trichomonas vaginitis, and the disadvantage is large toxic and side effect. The Chinese medicine irrigation solution disclosed herein is prepared by putting 27 kinds of herbs comprising patience dock root, senna leaf, cape jasmine, pagodatree pod, garden burnet, cacumen biotae,bitter orange, cortex magnoliae officinalis, longstamen onion bulb, areca peel, peach seed, Chinese angelica, radix scrophulariae, black sesame, hempseed, bunge cherry seed, honey, almond, Dictamnus dasycarpus Turcz, sophora flavescens, balsam pear, ilex latifolia thunb, Elephantopus scaber, polygonum cuspidatum, Saxifraga stolonifera, radix gentianae and licorice in water for soaking, then decocting with slow fire, filtering and removing the residues to obtain a liquid medicine. The Chinese medicine irrigation solution disclosed herein has the advantages of small toxic and side effect, shorttreatment course and high cure rate, and can avoid the adverse effects of applying western medicines.