Weapon-Target Assignment (WTA) as an important part of the aerial defense cycle has long been studied. Challenges are usually finding fast-computing methods to search optimal or near-optimal solution in cases of a large number of weapons and targets. This viewpoint is more mathematically considerable but practically has limited usage in the mentioned context. In this paper, a real-time search algorithm is proposed which decomposes the WTA problem and by decreasing the size of solution space and deleting impossible solutions, provides a real-time exhaustive search algorithm. Implementation of the algorithm for three typical scenarios shows excellent real-time performance and the possibility of finding exact solutions for large-scale problems.