The invention provides a heartleaf houttuynia herb injection and a preparation method thereof. The method comprises the following steps of: preparing distillate by using a certain quantity of fresh heartleaf houttuynia herb medicinal material through a steam distillation method; and adding accessories, lacking bacteria at the temperature of 115 DEG C for 32 minutes to obtain an injection, wherein the preservation condition of the fresh heartleaf houttuynia herb medicinal material is that: the collected heartleaf houttuynia herb medicinal material is stored at the temperature of not more than 30 DEG C for not more than 28 hours.