The large-scale distributed measurement system is based on the principle of intersection of multi-source observation. The relative position and pose relationship among the measurement nodes directly determines the overall performance of the system. The workspace Measurement Positioning System ( wMPS) is a typical representative of distributed measurement systems. Its orientation methods rely on the interchangeability of target reflector of the laser tracker to construct geometric constraints, which results in inevitable centering error existing at the receiving node of the system and affects the orientation accuracy. This paper studies a distributed system orientation method based on mobile cooperative target. Through designing a cooperative target integrating multiple receiving nodes, there is no need to accurately determine the structural relationship among the target receiving nodes, but to use the relative invariance of the spatial positions of the receiving nodes as rigid constraints to establish the relative position and pose relationship model of the base station with redundant optical plane intersection information. Combined with the initial value calculation model of resection orientation, the orientation result that is not affected by the interchangeable centering error of the receiving node is obtained. Finally, wMPS is used as the experiment verification platform. The results show that this orientation method avoids the high-precision interchangeability of target reflector, has good stability and effectively decreases the influence of the interchangeable centering error of the receiving node. Compared with traditional orientation method using standard ruler, the reference length measurement accuracy of this orientation method is improved by about 40% .