Abstract: After long-term use and research on CA6136 horizontal lathe, it is found that the positioning accuracy and impact resistance of the front tool rest are poor, and it is easy to get stuck in case of tool collision or impact. If you forcibly move the tool rest pull rod to change the tool, the pull rod will break and damage the machine tool parts, making subsequent maintenance difficult. In order to prolong the service life of the tool rest, it is necessary to study and improve its positioning mode. After analysis, three improvement schemes are proposed, and the optimal scheme is selected after structural design, force analysis and comparative study. The improvement is completed through machining, assembly and debugging, and the ideal effect can be achieved through long-term testing. The research results are worth reference and use for machine tool manufacturers.