The invention provides a machining method of a precision bearing seat. The machining method includes: material preparation, namely taking a blank as a precision die forging piece; rough turning, namely using a three-jaw chuck hard claw on an ordinary numerically-controlled lathe to clamp the forging piece, performing rough-turning on the outer circle and the outer-circle end face of the forging piece, turning around the forging piece prior to clamping the same with the three-jaw chuck hard claw, performing rough-turning on the other outer-circle end face and the circle, and boring thickly the inner hole and the inner-hole end face of the forging piece; heat treatment, namely performing annealing on the workpiece subjected to rough turning; finish turning, namely using the three-jaw chuck hard claw to clamp the workpiece subjected to heat treatment on a precision numerically-controlled lathe, and performing finish-turning on the outer circles, cut grooves and outer-circle end faces; using the three-jaw chuck hard claw to clamp the other outer-circle end face which is subjected to finish turning, and finely boring the inner hole and the inner-hole end face; cold treatment, namely performing cold treatment on the workpiece after finish turning; finishing, namely completing grinding of the inner hole, the outer circles and the end faces of the workpieces on a precision universal numerically-controlled grinding machine by the aid of the workpiece subjected to cold treatment with one-time clamping of the precision grinding clamp of the bearing seat, and machining of the bearing seat is completed. The machining method is high in machining precision and production efficiency.