In order to improve the measurement accuracy of articulated arm coordinate-measuring machines (AACMMs), a new kind of AACMM based on an indexing joint structure is proposed in this paper. The working principle of the indexing joint is introduced, and a kinematic model of the measuring machine is established based on this principle. The influence weight of the angle error for each joint on the measurement accuracy is analyzed by simulations, and the changes in the accuracy, measurement space and flexibility of the measuring machine before and after adopting the indexing joint are compared. The results show that the use of the indexing joint can effectively improve the measurement accuracy of the AACMM, and the replacement of the first two joints with the indexing joints has the most obvious improvement effect on the measurement accuracy, and has little influence on the measurement space and flexibility. The indexing joint-based AACMM can provide a new idea for the research of improving the measuring accuracy of the AACMM.