A method for measuring the thickness of liquid-lubricated film of end face and detecting the friction of end face of mechanical seals has been presented in this article. Eddy current sensors installed on the inner ring embedded in the stationary ring of mechanical seals are used to measure the thickness of the liquid-lubricated film. Acoustic emission sensor placed on the stationary ring base is used to detect the friction of end face. The micro scope condition monitoring of end face is of importance to ensure mechanical seals run normally. With a set of tests, the results demonstrate that the method is effective.