Abstract: The geological works in high-yield and high-effective (so-called "two high") mines are divided into three levels:the assessment of mining geological conditions of main seams in the range of the mine field;the detection of geological conditions in working area before mining;advance detection of geological conditions in fully mechanized coal face.The objectives to be attained,the working contents and the corresponding technical measures in the different levels are expounded.The author's viewpoint on the technical conditions of geological guarantee in high-yield and high-effective mines are presented,exhibiting the development direction of mining geological work from "extensive type" to "intensive type".