The goal of this research work is to find a Green function for a complex cracked (fractured) domain. There are several methods for obtaining a Green function for a particular domain. In this article we find a Green harmonic function for the upper half plane with a crack (linear fracture) in the given segment from 0 to i using conformal mapping theory, specifically the Schwarz Christoffel transformation and the conformal invariance method. The Green function obtained enables the construction of the Poisson Kernel, which in turn allows integral representations of solutions of boundary value problems for partial derivative equations.La meta de este trabajo de investigación es encontrar una función de Green para un dominio complejo agrietado (f...