Abstract: For the small diameter tube X-ray inspection in oil and gas fields, the technical key points of the field site radiographic inspection was introduced emphatically. The main technical characteristics of pipeline weld positioning, mobile X-ray machine translation distance, and film layout and testing operation were described. An analysis of the main points of each process was given. Finally the negative film assessment and weld repair notice representation method of defect location in the oil and gas pipe was presented in detail.