Abstract: In order to solve the problem of locating the leak point in a long-distance pipeline in service with a small diameter, this paper designs a fluid-driven pipeline inspection robot covered with a plastic sealing layer made of flexible materials. The relationship between the pressure difference needed to push the robot and the detection speed is analyzed by judging and locating the leak point through the changes of the flow pressure and the inner pipe diameter. Under the condition of the minimum pressure difference, this paper presents a structure design of a fluid-driven pipe robot based on a certain fluid density. The extrusion force of the pipeline on the robot proves to be the maximum pressure difference source second to fluid itself. The friction coefficient is measured, and the pressure of the robot is obtained by simulation experiments. Based on this, the response surface method is used to optimize the design of the robot. After the optimization design, both the maximum extrusion force and the pressure difference at the front and back of the robot in the pipeline reduce by 98.42%, and the average speed increases by 7.1%. The experimental results show that the robot can completely achieve suspension balance in this long-distance pipeline, thus minimizing the impact of friction, improving the detection speed and shortening the detection time. The external structure of the plastic sealing layer is designed by using double cone angle support, which can make the robot move forward and detect the leakage point in the pipeline under the action of small pressure difference.