The invention provides a workpiece clamping device for a cylinder printer. The device comprises two supports which are spaced by a certain distance, at least one guide supporting device and a movablepush-pull device are arranged between the two supports, a push-pull driving device connected with the push-pull device is arranged on one support, a workpiece supporting mechanism is further arrangedbetween the two supports, at least one pressing device with a locking function is arranged on the guide supporting device in a sliding mode, a middle rotating shaft is arranged at the position, abovethe workpiece supporting mechanism, on each pressing device, the two ends of each middle rotating shaft extend out of a pressing plate to be provided with a workpiece pressing head on each of the twosides, the top end of one of the two supports is provided with driving rotating shafts at the same position as the middle rotating shafts, the inner sides of the driving rotating shafts are provided with the workpiece pressing heads, the outer sides of the driving rotating shafts are provided with driving wheels, and rotating shaft driving devices connected with the driving wheels are arranged onthe supports. According to the device, the printing efficiency and printing quality of a cylindrical workpiece are improved.