A deposition system for winding of a large-scale superconducting magnet coil. First and second conductor supports withstand the weight of a bent conductor and allow the conductor to be lowered down in spiral and be placed smoothly onto a rotary table. The rotary table bears the weight of coils, rotates according to a contour of the coil and forwarding speed of the conductor, and tracks the winding trajectory of the coil accurately, which avoids the extra stress induced onto the conductor. The conductor placed on the rotary table is reliably clamped by clamping fixtures and adjustable rod to ensure the conductors to be placed on correct radial and toroidal positions. After treated by the deposition system, the conductor is placed to a corresponding position on the rotary table smoothly and accurately to achieve a high-precision contour control of the coil.