The invention discloses a portable tree digger, mainly comprising an engine, a gearbox, a transmission bar, a cutter disc, and hard alloy blades, wherein the engine is mounted at the top end of the gearbox and is used for driving the gearbox, one end of the transmission bar is provided with a bearing, the other end of the transmission bar is fixedly connected with the gearbox, a gear and the cutter disc are mounted on two sides of the bearing respectively, a gear is fixed to an output shaft of the gearbox, and a chain is engaged with the gear on one side of the bearing at one end of the transmission bar and the gear at the output shaft of the gearbox in order to perform transmission, driving the cutter disc to rotate, wherein a damping device is mounted in the gearbox. The cutter disc is provided with grooves for inserting the hard alloy blades, the cutter disc is provided with disc tooth posts, the disc tooth posts and the hard alloy blades are provided with screw holes that may serve for fixing bolts and facilitating detachment. The defect that a chain saw and steel bits easily break and damage when an existing tree digger and have high replacement cost is in operation can be overcome; therefore, the portable tree digger is better to use during tree digging.