Robotic arm plays a key role in industrial automation， which brings great benefits to various industries by improving productivity， reducing costs， improving product quality， etc.， and can appropriately solve the problem of labor scarcity caused by the aging population in China in the future. In this field， the relevant technologies of the United States， Japan and Germany are relatively mature， while China is in the stage of vigorous development. This paper mainly studies how to use a robotic arm to write fonts. Firstly， the GB2312 font library is used to search for feature points in the characters as path points through Python. Secondly， polynomial interpolation and other methods are used for trajectory planning， and MATLAB and Coppeliasim are used for simulation. Finally， control the Mirobot robotic arm to complete the writing of Chinese characters. The results indicate that the robotic arm can not only be used for writing， but also for batch writing data on metal surfaces， or laser engraving marks on materials such as wood and leather.