Abstract: Geosteering while drilling technology could be used for real-time judgement of whether drilling reservoir or not and judgement of its position, for active regulation of drilling orientation, in accordance with drilling parameter, logging while drilling（LWD） parameter, and other parameters. It has been generally acknowledged as a new drilling technology with the most promising future in 21st Century. In this paper, the general idea and major functions of the ground decision-making system of the geosteering while drilling system are put forward, and Visual C++ 6.0 could be used to fulfill the management and application of real-time drilling data. The ground decision-making system could be used to make inquiry, record data, draw real-time curve, and generate hole trajectory. It provides favorable technological support for explorers on the site to make decisions for its good interactivity, and it could be popularized and applied further.