The invention relates to a tunnel settlement convergence detector and a tunnel settlement convergence detection method. The detector comprises a detector main body, wherein a measuring device which is driven by a servo motor to rotate is arranged on the detector main body; the measuring device comprises a carrier; the carrier is connected to the detector main body through a rotary shaft; the rotary shaft is connected with an angle coder; and a laser interference distance meter and a gravity induction sensor with a level zero-degree output signal are arranged on the carrier. The method comprises the steps of original data detection and settlement convergence detection. The invention is simple in structure, convenient to operate, high in accuracy and high in stability, quick detection can be realized, one-time detection can be finished by only one person within a few minutes, time-saving and labor-saving effects are achieved, and the invention has an obvious technical progress; and meanwhile, the detection does not conflict with other engineering construction, all-weather real-time monitoring can be performed by using application software, and large settlement and instable settlement of a tunnel are early warned.