Abstract: The arc behavior of high-strength camera and welding electric signal acquisition system in the process of constrained arc welding of high-strength sandwich plate T-joints were studied. The results showed that the flux bands not only effectively solves the arc climbing problem in the welding process, but also changes the arc shape and heating characteristics, and significantly increases the arc stability; when the arc voltage is controlled at 23~29 V, and the welding current is controlled at 240~320 A, the groove width is controlled at 5~7 mm. Within the range of process parameters, the flux bands has a moderate melting height, and the arc can be well constrained. The distance from the arc to the bottom of the groove is equivalent to the distance from the arc to the side wall of the panel, mainly on the slope. The bottom of the mouth and the root of the side wall are stably burned, and a good T-joint with a fusion of the panel and the core plate can be obtained.