The invention relates to cable laying ship submarine cable burying machine lifting and dragging system matching equipment, in particular to a deflection angle detection device for a storage winch rope arranger in a double-winch system. A proximity switch is mounted on an upper supporting plate, a spring is arranged on a spring supporting seat, a shaft end cover is arranged above an upper rotating block and connected with the upper supporting plate through a screw, a position rod is mounted between clamp plates below the upper rotating block, the upper rotating block is connected with a lower rotating block through supporting cylinders, an adjusting hole is formed in the upper supporting plate, the horizontal mounting position of the proximity switch can be adjusted, adjusting holes are formed in the clamp plates below the upper rotating block and the position rod, the extension length of the position rod can be adjusted, so that a deflection angle range is adjusted, a steel wire rope penetrates the space between two supporting cylinders, and the rotating angle of a free end of the position rod is detected by the proximity switch. The deflection angle of the steel wire rope in cable deploying and retracting by winches can be accurately detected, the steel wire rope is stably and neatly arranged on a reel, smooth operation of the winches is ensured, and the service life of the steel wire rope is prolonged.