A provided preparation method for 4-chlorophenylhydrazine hydrochloride comprises the following steps: 1) under an acidic condition, at 5-10 DEG C, dropwise adding a sodium nitrite aqueous solution with a concentration of 20% into 4-chloroaniline to perform a diazo reaction and to generate a diazo salt; 2) under a room temperature condition, dropwise adding an ammonium sulfite aqueous solution into a solution of the diazo salt obtained in the step 1, heating to 50-60 DEG C and keeping the temperature for 3-4 h; and 3) at 50-70 DEG C, dropwise adding a hydrochloric acid solution with a concentration of 20% into the solution obtained in the step 2, keeping the temperature for 1-2 h, reducing the temperature, filtering, washing, discharging the material, and drying to obtain a finished product. The beneficial effects comprise that by using ammonium sulfite aqueous solution as a reducing agent in the reduction reaction, the problems are solved that sodium sulfite solid is easy to cake during material charging in a conventional technology and material charging is not easy to operate; ammonium chloride and ammonium hydrogen sulfate which are generated in the acidification reaction have high solubility in water, and crystallization precipitation is late, thereby facilitating performing of the acidification reaction in the solution and reducing side reactions; and the product crystallizes loosely, is good in fluidity, easy for material discharging and washing, and product quality and yield are both better than conventional production levels.