The present invention relates to a deflection angle automatic test device for flexible groove-type pipe joints for fire protection. The deflection angle automatic test device comprises a closed end pipeline, a water incoming end pipeline, a pipeline supporting device, a water pressure control device, a torque loading device, a leak detection device and an angle measuring device; the closed end pipeline and the water incoming end pipeline are connected by a flexible groove-type pipe joint test piece; the pipeline supporting device is used for supporting the closed end pipeline and the water incoming end pipeline; the water pressure control device is used for injecting water into the closed end pipeline and the water incoming end pipeline and performing water pressure control; the torque loading device is used for loading a torque to the flexible groove-type pipe joint test piece; the leak detection device is used for leak detection; and the angle measuring device is used for deflection angle measurement. With the deflection angle automatic test device of the invention adopted, the automatic test and result judgment of the deflection angle of the flexible groove-type pipe joint are realized, the burden of an operator can be decreased, human-made disturbance factors can be eliminated, and detection quality and efficiency are improved.