In recent years, with the emergence of high imitation handwriting, robot handwriting,electronic signature handwriting and other difficult handwriting,These are increasing the difficultyof handwriting identification. Therefore, it is necessary to deeply analyze the formation mechanismof handwriting, Improving the understanding of handwriting, So as to improve the accuracy ofhandwriting identification. This article introduces the traces of habits and their characteristics, analyzethe establishment mechanism of writing habits, further elaborate the composition and characteristics ofhandwriting, to explore the relationship between handwriting and the physical and mental characteristicsof the writer, In order to improve the deep understanding of handwriting.