A lubrication system includes a lubricator. A detecting unit includes an oil introducing part, multiple chambers, multiple blockage detectors and a processor. The oil introducing part is connected between the detecting unit and the lubricator. The oil introducing part communicates with the chambers. The blockage detectors are electrically connected to the processor and monitor transportation status of lubrication oil of the chambers. The processor judges the transportation status of the lubricating oil of the chambers by results from the blockage detectors. The lubrication system finds out blockage in the oil paths immediately so as to remove the blockage timely.