The present invention relates to a spent fuel dry reprocessing method for directly obtaining a zirconium alloy nuclear fuel, comprising: determining components and a ratio of a molten salt composition used for melting a spent fuel according to a requirement of reactor design on a zirconium alloy fuel and contents of actinium series metals in the spent fuel; melting the spent fuel in the above molten salt composition; and selecting an electrode pair for electrodeposition so that zirconium in the molten salt composition and uranium ions in the spent fuel or uranium and other actinium series metal ions are subjected to co-deposition, thereby obtaining the zirconium alloy nuclear fuel meeting a design requirement. The spent fuel dry reprocessing method provided by the invention is suitable for oxide spent fuel and metal spent fuel, and is simple and controllable in process, low in energy consumption, low in cost and easy to industrialize.