The invention discloses a live check method for a high voltage cable cross interconnection grounding system. The method includes the following steps: checking a wiring mode of two cross interconnection boxes of a cross interconnection section; applying a signal of a specific frequency to each connection board of a cross interconnection board in the first cross interconnection box, and receiving the signal in an adjacent grounding box; listing a theoretical value of the signal when cross transposition is correct under the wiring mode according to the wiring mode of the first cross interconnection box; matching the recorded result with the theoretical value; and comparing the test results of the first cross interconnection box and the second cross interconnection box. The live check method for a high voltage cable cross interconnection grounding system solves the problem that live check of the cross interconnection system is difficult when equipment is running.