Abstract: Considering the actual situations when the Myanmar-China Oil Pipeline (in China) is laid in mountainous areas, conventional pressure testing segmentation methods are analyzed, indicating some problems like multiple segments, long construction period, high engineering cost and difficult construction. Therefore, a new segmentation method based on the internal pressure under dynamic design is proposed. With this method, the internal pressure value at each point along the pipeline is set to the maximum practical operating pressure under the worst conditions, and then the pressure testing segmentation is conducted. This paper expounds the rationality of the method from the perspectives of design specifications and engineering practice, and also introduces the principle and steps of the method. The study results can provide significant guidance to the pressure testing of oil pipeline built in mountainous areas.