The handwriting characteristics of machine imitative signature in terms of writing style, layout, writing method are almost completely consistent with the imitated signature. A general analysis of the differences between machine imitative signatures and handwritten signatures in terms of various handwriting features makes little sense. On the contrary, there are more detailed differences on some handwriting characteristic like writing strength, writing speed and so on. In this experiment, the characteristics of stroke mark are taken as the research object, and the samples of human handwritten signatures are collected and the corresponding machine imitative signatures are made. The similarities and differences between them in stroke marks are observed and summarized by microscope. The results show that there are morphological differences between machine imitative signature and handwritten signature in ink dots, indentations, stroke width and thickness and so on. Machine-writing has strong repeatability and similarity in these features, and the same features always appear in other handwriting. Because of the different structure and function of the writing robot, the writing characteristics of the machine itself also affect the stroke characteristics of the machine imitative signature. For example, ink and white line features are not observed in machine imitative handwriting. In conclusion, the stroke marks of machine imitative signature have strong regularity and high similarity, while the stroke marks of handwritten signatures have strong randomness and rich changes. Affected by machine itself, the machine imitative signature and the human writing signature have obvious and fxed differences in stroke mark. It is a feasible handwriting inspection idea to identify machine-writting handwriting from the perspective of stroke mark.