This paper presents a study on the interaction of lateral vibration and friction vibration of a marine water-lubricated bearing when the bearing and stern shaft journal contact. The coupled vibration modes were modeled innovatively to analyze their interactions, where the lateral vibration response of the shaft journal into the normal load was applied to the dynamic friction force. The regular patterns were analyzed utilizing the theoretical derivation, numerical simulation and tests whose results show that the contacted motion statuses are relatively complicated and the feedback mechanism due to interference expressed as the term of K(b)C(0)r ' accelerates the instability of the coupled system in the negative area of the friction-speed curve.