Abstract: In view of the possible toxic and harmful gas emission from the penetration face of the goaf in Sandaogou Coal Mine，which endangers the working safety of the working face，a method of using poly⁃ urethane foam materials to plug the penetration face of the goaf is proposed，and the expansion，adhesion， foaming，anti-static and flame retardant properties of the plugging materials are analyzed，and the reason⁃ able matching ratio of polyurethane foam plugging materials is proposed.On this basis，polyurethane foam materials were systematically studied. The results show that the expansion time of the plugging material is 2min，the expansion ratio can reach 10 times，and the falling area of the coal block is only 4%，reaching Grade 4B. The test results meet the requirements of underground use.When the content of conductive car⁃ bon black is 1.5，the resistance order of magnitude can be reduced to 107，which can effectively prevent the accumulation of electric charges.When the addition amount of flame retardant 8316 is 21%，the oxygen in⁃ dex reaches the maximum value of 29.2%，which can achieve good plugging and flame retardant effects. The polyurethane foam plugging material has good adhesion with the coal body. After plugging the simulat⁃ ed pipe wall，under the wind speed of 25 m/s，it has no impact on the plugging situation，and the overall plugging effect is good，which can effectively solve the problem of toxic and harmful gas influx from the goaf penetration face，and provide guidance and reference for the plugging of the goaf penetration face in mines with similar conditions.

Key words: goaf, penetration face, plugging, polyurethane