Abstract: Pipes for natural gas storage and transmission will produce oxide skin on the inner surface after long-term's usage, which will plug the outlet valve and lead to a failure of the high-pressure pipe. To solve this problem, high-pressure water jet flow technique is presented and the characteristic and effect mechanism of the high-pressure water jet flow for washing the oxide skin are introduced in the paper. Work process, structure and basic parameters of the high-pressure water jet flow system is described, and economic analysis and effectiveness evaluation of the technique are also carried out.