As a typical rigid-flexible contact system, the water-lubricated rubber bearing-rotor system (WLRBRS) is prone to friction-induced vibrations under extreme operating conditions, which compromises the reliability and stealth performance of naval vessels. Traditional research methods are insufficient to deeply investigate the dynamic characteristics of contact interface, resulting in unclear mechanisms behind friction vibration. This study constructs a visualized friction interface, utilizing high-speed camera, vibration and force sensor, and employs digital image processing method to analyze the contact and dynamic characteristic of the WLRBRS. The research indicates that: Friction vibration originates from stick-slip at the contact interface. The occurrence of 'Chatter' and 'Squeal' is governed by whether the relative velocity of the friction pair is zero. The friction vibration of WLRBRS is essentially the coupling of bearing and rotor vibration.