Abstract: In this paper,a method,by which the swing axle torsional angle of sheet feeding shaft of printing press is measured based on encoders,is introduced.Then,the design method of the data acquisition system and signal processing software for measuring torsional angle is discussed in detail.The swing axle torsional vibration of test bed designed by the author is measured by the measurement system also designed by the author based on the ZonicBook/618E data acquisition device,and the analytical results are obtained.Test results proved that the swing axle torsional vibration signal could be measured by this method.The presented method to measure torsional vibration signal of swing axle is put forward for the first time in China and it might provide important reference for research in the related field.