The SVD system could automatically sense the well deviation and automatically adjust the side force of the tool so that make the well hole track inclines to vertical situation, which can realize prevent from deviation on its own, correct the deviation at real time and undertake drilling quickly and in good quality.  While drilling at the high and steep formation or the deviation intend formation, the SVD system could effectively resolve the contradiction between deviation prevention and increasing drilling pressure, so that dramaticly enhance drill speed and improve well hole quality.
 The Automatic vertical drilling system is composed of Well deviation sensing system, Oriented Control System and signal transmission system.
 Real time sensing inclination’s  gravity signal which will drive the device to form high and low pressure fluid channel inside and outside drill string .The pressure difference will drive lateral push device to high side of sidewall , sidewall reaction will push the drill bit to low side . The lateral push device will not work in other positions of the well. So as to sense and modify inclination, fasten drilling and improve well quality.