Abstract: Traditional method for underground gas pipeline repair has a couple of problems such as large scope roadbed destroying, environmental damage and traffic interference. Non-excavation technique is found to be an effective way for urban underground gas pipeline repair. The repair system is mainly composed of vacuum machine, core drilling machine, transportation vehicle, portable drilling machine, gas shovel, etc. Working principle of the system is that air compressor as the power source is utilized; roadbed cutting is made by core drilling machine; vacuum machine, air compressor and air shovel are used to dig the soil layer; pipe is repaired; soil is backfilled; roadbed is restored. The system effectively integrates the roadbed cutting technique, vacuum digging technique and non-excavation repair technique, which solves the problems in coating repair and sacrificial anode installation with simple operation, safety and reliability, low cost and high efficiency.