Abstract: Deep hole processing for pipe parts is an issue of mechanical processing.According to the deep hole processing for a bent tube of the main pipe AP1000 used in nuclear power, a follow-up method for processing the deep hole of elbow pipes is put forward Three boring bars and a direct driven rotary motor are adopted.They are linked together by three rotational joints, and then fixed on a special purpose machine tool.Thereby, the curved hole of the main pipe for nuclear power can be processed.After theoretical analysis and calculation for each interpolation parameter, the theoretical calculation formula for the next linkage programming is obtained.