An optimized presswork definition detecting method comprises the steps of: generating a test chart used for detection of presswork definition; converting the printed and output test chart into a digital image by utilizing an image capturing device; performing detection and calculation on a definition quality index based on the digital image of the printed test chart; performing identification on the presswork definition based on an established presswork definition quality detection model. Quantitative description for reflecting the presswork definition is provided in a value way to replace a qualitative subjective visual inspection definition identifying method which is used for a long time in the printing industry, so that the optimized presswork definition detecting method overcomes the technical problems of subjectivity, inconsistence, low efficiency and the like existing in the current identifying method.