The robustness and stability of digital watermarking image is closely related to the distortion caused by the print-scan process. Printing is the conversion process between digital images and halftone images, and causes low-pass filtering attack, halftone attack and geometric attack into the watermarking image; scanning is the reverse process of printing, which leads into low pass filtering attack and geometric attack. Thereinto, nonlinear distortion of pixel values on digital watermarking image is caused by low pass filtering attack and halftone attack, while geometric attack causes the geometric distortion. The correction countermeasures for the nonlinear distortion of pixel value include optimally setting the resolution of printer or scanner, correcting the gamma value, using the spatial low-pass filter to remove Gauss noise, etc while the reductive countermeasures for geometric distortion consists of overcoming geometric asynchronous attacks by embedding the cyclical redundancy , designing template embedding to achieve synchronization, and so on. Key words：print-scan；digital watermarking；nonlinear distortion of pixel values；geometric distortion；reductive countermeasures for distortion