The invention discloses a precision core drilling machine. The machine includes a base, a threaded rod, an anti-deviation device, an actuator assembly, a vertical engine, a hollow drill, a top base, a rotating hand wheel and a leading screw, wherein the actuator assembly is composed of a driving shaft, an outer shell body, a planetary gear train, a big sun gear, a transition gear, a tail end gear and a driven shaft; the side wall of a planetary gear groove is provided with annular gears, and the planetary gear train includes a small sun gear and small planetary gears; the driving shaft is successively connected to the small sun gear and the big sun gear in a key joint mode; one end of the transition gear is meshed with the big sun gear, and the other end of the transition gear is meshed with the tail end gear; the leading screw is connected to the internal of a nut sleeve, the driven shaft is connected to the tail end gear in a key joint mode, and the bottom of the driven shaft is connected to the hollow drill. The precision core drilling machine has the advantages that a series of deficiencies in the adoption of belt transition are abandoned, and transmission is much stabler during drilling; the rotation of the hollow drill is much stabler, deviation does not occur easily, and obtained core samples are more precision and uniform.