The utility model belongs to the technical field of medical instruments of the stomatological department and particularly relates to an oral cavity observation mirror. The oral cavity observation mirror comprises a mirror frame, a lens embedded in the mirror frame, a handle with one end fixedly connected with the outer circumference of the mirror frame and a pressing sheet fixedly installed on the outer circumference of the mirror frame, the pressing sheet is designed into a rectangular sheet with the bent surface, the direction of the long side of the pressing sheet is the same as the extending direction of the handle, and the lens is a double-sided lens. When the oral cavity observation mirror is used, the pressing sheet of the oral cavity observation mirror can press the tongue to avoid too large activity range of the tongue, and the problem that a doctor cannot observe and diagnose due to the fact that the oral cavity observation mirror is blocked by the activity of the tongue is solved.