The space is very limited in Taiwan. Table tennis has been progressively promoted as one kind of sports. Since the volume is small and the weight is very light for table tennis, the speed and variation change dramatically. Thus it is entertaining and attractive for a people. Table tennis also has been regarded as a major sport in many countries all over the world. In addition, it has been included as a regular event in Olympic Games. Recently, table tennis is welcome and widely promoted in Taiwan. Many competition games are held every weekend. However, the edge ball event sometimes occurs during the competition. This event is difficult to judge by a referee. Wrong judgment always occurs and impacts the fairness for players. In this study we attempt to analyze the difference of spectral properties between the edge and the on-table balls. Hence, to accurately detect an edge ball can be performed in a table tennis game. Experimental results show that the spectral properties of edge and on-table balls are different. To accurately detect the edge ball by sound properties is available and can be further developed.