The invention relates to the field of mechanical processing, in particular to an online measurement and compensation method of position error of an inner wall surface of a deep pipe. A non-contact online intelligent detection system of the online measurement and compensation method of position error of an inner wall surface of a deep pipe comprises a deep pipe, an industrial control computer, a support, a panel, a cutter bar, a triangular displacement sensor, a boring cutter, a seal cover, a first bar core, a first displacement sensor, a reflector and a second bar core, wherein the deep pipe,the industrial control computer, the support, the panel, the cutter bar, the triangular displacement sensor, the boring cutter, the seal cover, the first bar core, the first displacement sensor, the reflector and the second bar core are arranged on a center frame and a chuck; the cutter bar is arranged in the deep pipe; the boring cutter is arranged at the front end of the cutter bar; the seal cover is arranged at the top end of the cutter bar; and the panel is arranged at the tail end of the cutter bar. The online measurement and compensation method of position error of an inner wall surfaceof a deep pipe makes a difference between final regulation and control parameters and initial processing parameters, solves the relative error, and provides a possible error range for the subsequent processing parameter selection, so as to enable an operator not to strictly adhere to the position error prediction map and consider the efficiency in the error range during the initial processing period, and greatly expanding the flexibility and adaptability of the method.