The invention relates to a door opening machine achieving positioning by means of an absolute value encoder. The door opening machine comprises a bottom plate, a drive gear, a motor and a positioningassembly; the drive gear, the motor and the positioning assembly are arranged on the bottom plate; the drive gear meshes with a rack arranged on a door or a door frame; the motor is connected with thedrive gear to drive the drive gear to rotate to drive the door to be opened or closed; and the positioning assembly is composed of a pedometer and a transmission gear, the transmission gear meshes with the drive gear and is fixedly connected with an input shaft of the pedometer, and a pedometer which achieves calculation by adopting the absolute value encoder is adopted as the pedometer. According to the door opening machine achieving positioning by means of the absolute value encoder, precise positioning is achieved by adopting the pedometer which achieves calculation by adopting the absolute value encoder, the door can be opened to the any set position through the door opening machine, and the purpose of precisely controlling the door opening degree is achieved.