Currently in the field of deep geological core drilling，wire-line core drilling is the most commonly used drilling technology. Owing to annular size of wire-line core drilling is smaller， have no choice but to adopt the method of enlarging the drill bit， solve problems such as high pump pressure and high excited pressure causing hole-wall instability. In deep hole construction， the problem of annular clearance can be solved by increasing the drill bit to the upper caliber without lowering the upper casing. There is also an additional level of spare caliber. This article analyzes the drill pipe capacity of wire-line coring drilling， The theoretical basis for cross bore wire-line coring tools is proposed. The drilling tool has been designed and processed in a complete set and continuously improved in application practice. It provides great help for drilling structure design and complex formation drilling in the field of deep geological core drilling， Achieve good application results. In order to meet the requirements of long hole coring in geothermal drilling， a design scheme for large diameter wire-line coring tools was proposed， further expanding the scope of use of wire-line coring.