The invention provides a preparation method of a nuclear fuel FeCrAl/Zr bimetal composite pipe and belongs to the technical field of bimetal composite pipe material preparation. Firstly, by means of alloy smelting, hammer cogging, solid solution treatment, pipe blank machining and pipe material cold rolling, a covering layer pipe and a base layer pipe needing to be composited are obtained. Then inner and outer surface treatment is performed on the base layer pipe and the covering layer pipe, then the two pipes are connected together in a sleeved manner, one end head is closed, and cold finishrolling machining is adopted for performing rolling compositing on the bimetal pipes; and finally, inner and outer surface cleaning is performed, head cutting is performed in a wire cutting method, and a composite pipe finished product is obtained. The method is suitable for the condition that a FeCrAl series alloy and a Zr and Zr series alloy correspondingly serve as the covering layer pipe and the base layer pipe, and is also suitable for forming of a composite pipe of alloys difficult to deform. The method has the beneficial effects of being simple in process, high in production flexibilityand low in cost.