And the pipe disinfection system using ozone in the invention is an agitator tank receiving the raw water, ozone, and dry ice, and the agitator installed in the agitator tank, and the raw water feed pump, and the ozone generating apparatus, by mixing ozone with the raw water stirrer and a venturi injector to send into the tank, and agitator motor for rotating the stirrer, a refrigerator connected to the agitator tank to freezing the raw water containing the ozone is about 70% to 85%, for feeding dry ice into the agitator tank and the dry ice input port, the ship ozone decomposing apparatus for decomposing to release the fold ozone generated as a by-product from the agitator, and the ozone concentration measuring device which is connected to the agitator tank bottom piping, connected to the stirrer bottom piping ozone water by the venturi injector a and the ozone water circulating pump for circulating, first connected between the ozone water pump for transferring the frozen ice into the pipe, a first valve disposed between the water supply pump and a venturi injector, the ozone generator and the venturi injector and a second valve, with the third valve disposed between said venturi injector and a stirrer tank, with the fourth valve is provided in the ozone water circulating pump rear end, and the fifth valve installed in the branch pipe of the stirrer tank bottom pipe, a stirrer, a side and the viewing window, and a manhole for maintenance in a stirrer tank, which is installed in, and consisting of a controller and power supply unit for controlling the agitator motor, the water supply pump, a venturi injector, the ozone water circulation pump, an ozone water pumps, valves, etc. In addition, the pipeline disinfection with ozone comprising the steps of supplying a mixture of raw water and the raw water feed pump in a stirrer tank, with stirring the raw water containing ozone in a stirrer tank, the raw water contained by operating the chiller ozone preparing a freezing condition of 70% ~ 85% and, to that consisting of the raw water containing the ozone in said freezing step of injecting the disinfecting and cleaning pipelines by the pipe using the ozone water pump characterized.