A Taguchi methodology study of the plasma spraying thermal barrier coating (TBC) layer is presented. The experiment parameters were designed by a L8-style orthogonal arrays approach. A Taguchi analysis was conduc-ted through the results of the coating properties which were affected by plasma spraying parameters. Zirconia (partially stbilized with ytrria: PSZ) was sprayed on TiAl intermetallic compound substrates, The coating layer was characterized by thickness microstructure and porosity using SEM and Image analyzer. The coating quali-ties are discussed with respect to thermal barrier effect thermal cycling test6 and adhesion strength test. An optimum condition of plasma spraying process which are derived from the Taguchi analysis could be found for high quality TBC.