For the precise estimation of aircraft part damages in warfare, Lanchester Equation and reliability project theory are used to solve the problem. Focusing on the internal and external factors that affect the aircraft part damages, introduce the equivalent area into aircraft part, puts forward the estimation method of aircraft part damage based on reliability and Lanchester Equation by qualitative analyze and quantitative calculation, and illustrates with an example. This method combined the experience calculation with the analog calculation, can meet the need of accurate maintenance support in future warfare.