The invention discloses a preparation method for urapidil, and relates to an inverse phase transfer catalysis method for preparing urapidil, and belongs to the technical field of organic synthesis. The method comprises the following steps that: water is adopted as a solvent; an inorganic alkaline substance is adopted as an acid binding agent; 6-(3-chloropropyl)-1,3-dimethyluracil (I) reacts with 1-(2-methoxyphenyl)piperazine hydrochloride (II) in the presence of an inverse phase transfer catalyst to generate 6-[[3-[4-(2-methoxyphenyl)-1-piperazinyl]-propyl]-amino]-1,3-dimethyl-uracil (III, urapidil). With the method, the high-selectivity and high-yield preparation of the urapidil can be realized; the prepared urapidil has high purity, wherein the purity of the urapidil is more than 99.5%;the conversion rate is high; the yield can reach 80%; the reaction conditions are mild; the selectivity is good; the post-treatment is simple; the method is environmental-friendly, and is suitable for the industrial production.