Aiming at the problem that the mental workload of the workers in the manufacturing workshop is too heavy, causing errors and affecting the efficiency of the process, a mental workload evaluation method is proposed to reduce the risk of workplace injuries and improve the accuracy of operations in the workshop. Design two sets of experiments of 20 events, take the mental load results measured by the PAAS scale and WP scale as the dependent variable, through the NC lathe programming software, simulate the work content of the NC lathe programmer, and compare the PAAS scale and the WP scale. The effectiveness of the table used in the intelligent manufacturing CNC workshop is studied. The experimental result is that the sensitivity of PAAS scale is better than WP scale, and its F value is higher than WP scale 7. 494. In terms of aggregation validity, both scales performed well. It is concluded that the PAAS scale is suitable for the evaluation of the mental workload of the CNC lathe operators in the intelligent workshop. At the same time, the multidimensional characteristics of the WP scale can clearly indicate the influencing factors of the subject’s mental workload.