In this paper we calculate the production of a charged top pion in association with a W boson via gg fusion at the CERN Large Hadron Collider in the context of the topcolor assisted technicolor model. We find that, the total cross section of pp --> gg --> W^{pm}pi_t^{mp}, is several dozen femtobarns with reasonable values of the parameters, and the total cross section of pp --> W^{pm}pi_t^{mp} can reach a few hundred femtobarns when we consider the sum of the contributions of these two parton subprocesses gg --> W^{pm}pi_t^{mp} and bbar{b} --> W^{pm}pi_t^{mp}.