Oil wear particle can offer wear condition for marine machinery. The shape, size and composition of wear particle can supply important information for diagnosing the type and severity of marine machinery faults. Through oil wear particle detection, potential marine machinery fault diagnosis can be found early, thereby reducing the risk of marine machinery failure diagnosis and improving the reliability and service life of marine machinery. This review summarizes the detection methods, technical characteristics and research progress of oil wear particle detection sensors applied in marine machinery condition monitoring. Oil wear particle detection sensors are divided into impedance-based particle detection method and non-impedance-based particle detection method. Impedance-based method includes inductance, capacitance and resistance principles. Non-impedance-based method includes image processing, optical and acoustic principles. Finally, it points out the future development trends and novel ideas for the oil wear particle detection sensors employed in marine machinery.