The invention aims to provide a corrosion-resistant flux-cored wire and a preparation method thereof in order to meet the welding requirements of large aerospace structural parts. A welding joint can obtain high connector comprehensive mechanical performance. The flux-cored wire has good strength and toughness, especially excellent corrosion resistance, and is not prone to forming brittle intermetallic compound phase, and a welding connector with high performance can be obtained easily. The method for preparing the flux-cored wire is simple, convenient to implement, efficient, good in adaptability and convenient to popularize.