The Houxianyu boron ore district in Yingkou of Liaoning Province is a new producing area of serpentine jades, in which Yingkou jades display the characteristics of rich Mg,high Fe and dark color. In this paper, the metallogenic process of the Yingkou jade is discussed based on an analysis of petrology, petrochemistry and geochemistry of the jades, in combination with the geotectonic background, data of dating and the experimental results of the MgO-SiO₂-H₂O system. The results show that the protolith was magnesium peridotite and carbonatite which was replaced by metamorphic hydrothermal fluid from granitization granite. It is held that the serpentine jade deposit was mainly formed during 1.95～1.85 Ga, with the pressure close to 500×10⁵～2 000×10⁵ Pa and temperature 400～250℃, suggesting that it is a mesothermal metamorphic hydrothermal metasomatic deposit.