The present invention relates to an oil-water separation apparatus and discharge monitoring system of a ship. The system comprises: a power supply part which is provided in a ship and supplies electric power; an oil-water separation unit for receiving power from the power supply part to separate oil and water from each other; and a monitoring module for tracking, in real time, operation status of the power supply part and the oil-water separation unit, the module including a controller, wherein: the oil-water separation unit comprises an oil-water tank, a connection pipe connected to the oil-water tank, an oil-water separation pump disposed on a connection pipe line, and an oil-water separation filter assembly for separating oil and water supplied from the oil-water separation pump; and the oil-water separation filter assembly comprises a housing having an introduction part and a discharge part for oil and water, a guide member for guiding oil and water flowing into the housing through an inlet port in a spiral direction to form a swirling flow, a first oil filter for primarily separating oil and water flowing in a spiral direction by the guide member via centrifugal force, an adsorption agent disposed on the upper side of the first oil filter to adsorb separated oil thereon, and a second oil filter disposed inside the housing to secondarily separate the oil and water filtered through the first oil filter.