Adjustable drill bit for coal mine exploration and using method

The invention discloses an adjustable drill bit for coal mine exploration and a using method, and relates to the technical field of coal mine exploration, the adjustable drill bit comprises a drill bit, the top surface of the drill bit is fixedly connected with a shaft body through a telescopic assembly, the top surface of the shaft body is fixedly connected with a mounting block, the arc-shaped surface of the shaft body is provided with a drilling auxiliary assembly, and the inner wall of the mounting block is provided with an adjusting assembly; a connecting assembly is arranged on the top face of the mounting block, and a positioning assembly is arranged on the arc-shaped surface of the mounting block. When a hard rock stratum is drilled, a magnetic block is firmly attracted through an electromagnet, a drilling sheet is closed, then a connecting rod is driven to rotate through a drilling driving device, and therefore a drill bit rotates for drilling, when a soft rock stratum is drilled, the drill bit can b