With the depletion of coal resources in China, a large number of mines have been closed, leaving a large number of underground goaf sites. Many chemical enterprises dump chemical waste liquor into abandoned mines, which leads to groundwater pollution accidents in mining areas and threatens the safety of groundwater sources. There are very few emergency cases and experiences in dealing with pollution accidents under such complex site conditions. Taking the emergency treatment of groundwater pollution grouting curtain in an abandoned mining area in North China as an example, this paper builds a threedimensional geological model based on the analysis of geological conditions, the description of underground space structure and groundwater flow field in the mining area. Foundation design and implementation of curtain grouting project, study the important content and determinants of emergency disposal of curtain grouting under complex site conditions, and use the monitoring results of groundwater samples in the site, analyze the distribution characteristics and differences of pollutant concentration inside and outside the curtain, find out the law of groundwater movement, and evaluate the effect of grouting curtain. The results show that the curtain grouting project in the area of 100m around the accident well has remarkable plugging effect on pollutant transport, and the difference of pollutant content between inside and outside the curtain grouting is obvious. The results of the first stage show that the highest concentration of dichloromethane in groundwater is 1390 μg/L in the curtain grouting area, and the highest concentration outside the curtain area is only 8. 07 μg/L. The second stage results show that all areas with the detected concentration of pollutants are greater than 5 μg/L are within the curtain area, and none of them are detected outside the curtain. At the same time, the distribution characteristics of pollutants indicate that groundwater migration along roadways has become the most important form. The accurate description of underground space structure is an important factor to determine the effectiveness of curtain grouting project.