The bale knotter is the core components of the baler. To understand the working principle of the bale knotter more deeply, more and more researchers have built varieties of the knotter test bench. But this bale knotter test bench could not get the motion state of D-bale knotter and the tension of cord synchronous in the process of straw baling, a set of D-bale knotter movement and cord tension information synchronous acquiring system in real time was set up in the existing square baler. In order to achieve the goal of synchronous acquiring information, a synchronization module was designed for synchronous trigger high-speed photography and tension sensor. In order to verify performance of the system, a test was carried out under the condition of 1 000 Hz. The object of this test was wheat straw. Four groups of tests were carried out. From the tests it can be found that the number of target images captured by the high-speed photography and the number of target data captured by tension sensor were the same, and the feature points of D-bale knotter movement and variation coefficient of peaks of cord tension corresponding to the tooth plate degree was less than 3% in different sets of the tests. From the tests it could be known that the system can get the information of D-bale knotter movement and cord tension at the same time. The motion sequence range of D-bale knotter was obtained based on the information of knotter movement and cord tension. The motion sequence was more accurate than the existed motion sequence got by other researchers. The accurate motion sequence chart of the rope disc, bill hook and knife lever were got from the motion sequence. It could help to understand the working principle of D-bale knotter more clearly. The synchronous acquiring system built the foundation of the geometrical conditions for D-bale knotter. It was very useful for the research of D-bale knotter.