The invention relates to a grounding block, a grounding structure using the same, an insulator assembly, and a GIL. The grounding block comprises a ball seat in conductive connection with a corresponding grounding block support seat; a ball slot is formed in the ball seat; a conducting ball is assembled in the ball grove in a rolling mode; and the outer end of the conducting ball protrudes from the ball slot and is in contact and in rolling cooperation with the inner wall of a cylinder of a GIL. A plurality of rolling bodies are arranged between the conducting ball and the ball seat in the ball slot and are in contact and in rolling cooperation with the conducting ball and the ball seat respectively. Besides, a limiting structure for preventing separation of the conducting ball and the rolling bodies from the ball slot is arranged on the ball seat. On the basis of a universal ball structure, when an insulator is installed in the GIL cylinder in a sliding mode, the conducting bal and the rolling bodies are in rolling cooperation, so that a problem that the conducting ball can not roll smoothly due to direct contact between the conducting ball and the spring and thus the conducting ball is scratched or separated during the sliding assembling process to cause unreliable grounding in the prior art can be solved.