In the laid HDPE main pipe, or in the new optical cable route, the main pipe and micro pipe can be pre laid, which can be laid through the pipe or blown out by the cable blowing machine. The number of microtubules that can be placed in the main pipe mainly depends on the requirements of mechanical protection. The total cross-sectional area of microtubules (calculated based on the outer diameter of microtubules) shall not exceed half of the cross-sectional area of the main pipe. Fill the microtubule with continuous air flow, and use the air flow in the pipe to push and pull the surface of the microtubule to lay the microtubule.