The invention discloses a preparation method of an injection-use oxaliplatin freeze-dried preparation. The method comprises the steps that: A, pre-freezing is carried out, wherein a quick-freezing process is adopted; a freeze-drying cabinet is cooled to -5 DEG C to -10 DEG C; when a sample is delivered into the cabinet, heat-conduction oil temperature is rapidly set as -45 DEG C; and when the temperature of the product is consistent with that of the heat-conduction oil, the temperature is maintained for 3-4h; B, sublimation-drying is carried out, wherein the temperature of the heat-conduction oil is rapidly increased to -10 DEG C with a speed of 1 DEG C/5min; when the temperature of the product is similar to that of the heat-conduction oil, the temperature of the heat-conduction oil is rapidly increased to 0 DEG C with a speed of 2 DEG C/5min; when the temperature of the product reaches 0 DEG C, sublimation-drying is finished, wherein a total time of the process is no shorter than 15h; C, vacuum-drying is carried out, wherein the heat-conduction oil is heated with a speed of 2 DEG C/5min; the temperature of the product is increased to 30+/-2 DEG C, and the temperature is maintained for 2-4h; and D, a nitrogen filling treatment is carried out, wherein nitrogen is filled under a vacuum state; the preparation is plugged, and is fetched from the cabinet. The freeze-dried preparation provided by the invention has the characteristics such as loose product, stable quality, fast re-dissolving, and good clarification degree.