The invention relates to a polyimide film sintering powder and mica tape winding copper flat wire and a preparation method thereof. Two layers of insulation materials are wound outside a metal wire, the inner layer is a sintered polyimide film, and the outer layer is a mica tape. The electromagnetic wire has good voltage and heat resistance, high mechanical strength and strong corona resistance. The preparation method comprises the following technical routes: conductor straightening, conductor polishing, film winding, high-frequency heating, melting, adhesive sealing, mica tape winding and rolling. The invention integrates the production technical routes by improving a high-frequency device, a mica winding device and other devices, the quality of the copper flat wire is ensured, meanwhile, the mechanical property of the copper flat wire is increased, the production flow is shortened, and the production efficiency is increased. The invention is suitable for composite insulation winding coils of large-sized motors and electric appliances, such as wind driven generators, and the like.