In the process of shuttle loom, the angle between the shuttle of air-jet loom and the lowest point of weaving surface. According to the training data of air-jet loom technicians, the lowest point angle of air-jet loom refers to the angle formed by the shuttle of air-jet loom and the lowest point of weaving surface during the shuttle process. The size of this angle depends largely on the specific air-jet loom model, and it will be different because of the different machine structure and working principle.