A speckle metrology technique called dynamic white-light digital speckle photography is proposed, and an automatic measurement system of dynamic displacement or strain field is developed. The system procedure is designed so that the flashing illumination, the CCD camera, the grabbing card and the analog-to-digital converter can all work simultaneously. Two specklegrams of the specimen, one before and one after the deformation are captured. The time delay between two exposures is controlled by setting a certain numeral value in the Boxcar and the dynamic displacement in the deformation process of the specimen is recorded in serial specklegrams. The system is tested successfully.