Abstract: In order to analyze the load distribution on the main shaft,a testing method is proposed to indirectly measure the resultant force acting upon the needle bar which is the terminal actuator of the main-shaft system in a carpet tufting machine.Most testing experiments are performed in the following cases: measuring forces upon the needle bar in a single period and forces in different revolutions. This study has shown that with the increase of the speed of the main shaft the impulse on the needle bar become obvious,and the pull force upon the bar increases and varies sharply,but the maximum press force varies insignificant.The process analysis has been carried on by using the experimental data,and then methods of gradually advancing the yarn feed time or properly decreasing the base fabric′s tension are proposed to improve the load distribution.The experiments above and the related process analysis will also provide technological basis for further analysis of the equivalent force moment on the main shaft.