The knot-forming motions of knotters are difficult to directly observe, and knotting tests are labor-intensive and time-consuming. To address these issues, a novel test bench motion scheme was proposed to simulate the bundling process of a bale, and a performance test bench for a single-knot knotter was developed under controllable indoor conditions. The bench can verify the working principles of different knotters and assess the knotting success rate. To meet the requirements of unattended and safe operations for long-term continuous knotting tests, an automatic control process for the test bench was constructed to identify the knot-releasing failure and twine breakage fault based on monitoring the pressure of the simulated bale. By establishing the corresponding relationships between knotting actions and image states, a test and analysis method for detecting the motion timing sequences of the knotter was developed. This allowed us to obtain a motion timing diagram of the knotter, which can provide references for its reverse design or performance evaluation. The results of the continuous knotting tests show that the tested knotter achieved a knotting success rate of 99.57%, and the test bench can meet the performance testing requirements of the knotter.