Abstract: The influencing factors of radioactive waste water underground migration areanalyzed, the radioactive waste water migration protection conditions of underground and ground nuclear power plant is contrasted, and the ideas and specific engineering protection measures for radioactive waste migration protection of underground nuclear power plant are systematic proposed, that is, all radioactive waste water security measures of ground nuclear power plants are completely preserved and make full use of the natural protective properties of the rock, the additional closed, dewatering and other reliable engineering measures are set in the surrounding rock mass, the migration channel of radioactive waste water is blocked, at the same time, the collection, disposal and monitoring system are also set. The effect of above protective measures is remarkable by numerical analysis, and the produced radioactive waste water of underground nuclear power plant is controlled in severe accident condition.