The invention discloses a preparation method of a cross-linkable and curable casing damage plugging agent. The preparation method comprises the following steps: preparing an agent A, and then preparing an agent B, and finally, mixing the agent A with the agent B to form the plugging agent. The plugging agent prepared by the method provided by the invention is applicable to either blast hole plugging of a conventional oil-water well or casing damage well repair; the plugging agent is capable of plugging wherever the plugging agent goes; and therefore, lots of operating time and cost are saved.