The work aims to solve the problem that the hiding effect is not good and the hiding information is easy to imitate regarding the information hiding technology of current halftone screening. Based on the principle of the minimum threshold matrix screening, a kind of matrix rotation screening algorithm was developed to generate the specially shaped dot applied in the halftone information hiding technology. The generation of specially shaped dot by the proposed method overcame the defect "breakpoint" of traditional dot likely to occur during information hiding. The hidden visual invisibility was improved, and the dot shape changed according to the matrix design. As it was not easy to imitate, the security coefficient was improved. The specially shaped dot generated by matrix rotation screening provides better guidance for the application of the information hiding technology of halftone screening in the actual production.