In recent years,airports in our country implementing radar control have successively published minimum vectoring altitude （MVA） charts. During radar guidance,controllers often need to guide aircraft to deviate from standard instrument flight procedures. As there are no specific standards in our country for obstacle assessment below MVA in radar-guided areas,it is impossible to confirm the safety of aircraft over obstacles during initial stages of takeoff and missed approach when flight altitude is below MVA. Therefore,this paper studies the method of obstacle assessment for guidance below MVA,providing ideas and theoretical references to address the aforementioned issues and to fill the gap in domestic regulations and standards.