During the coating of components like rolls the major parameters are easily to control. But this is not sufficient to guarantee and stable a high coating quality. Additionally non-controllable parameters, e. g. nozzle wear, influence the process mainly. For this purpose a new testing method is necessary. On base of the acoustic emission analysis a testing equipment was developed in order to control the spraying conditions. In this investigation acoustic emission is applied to anlyse the signals generated by the impact of the molten particels on the component surface. The analysis of the signals is carried out in combination with a new classification method. The results of controlling APS(Atmosperical Plasma Spraying)-process during the disposition of a Cr2O3- coating will be presented. Paper text in German.