<p>The present invention relates to a piracy detection method of a vessel capable of detecting a piracy by using a radar signal included to prevent a vessel collision. The piracy detection method comprises; a step of extracting initial determination information to determine a vessel suspected to be pirates through an analysis by receiving a signal of the radar installed in a vessel to prevent a vessel collision; a step of determining the vessel suspected to be pirates based on the extracted initial determination information; a step of obtaining an image of the vessel suspected to be pirates by operating a camera if the vessel is determined as the vessel suspected to be pirates; a step of controlling the obtained image to record and determining the vessel suspected to be pirates finally by analyzing the obtained image; and a step of checking a warning mode and transmitting a warning broadcasting through the broadcasting in the vessel if the warning mode is an automatic mode.</p>
