Disclosed in the utility model is a probe mechanism for a pipeline acceptance check detector. A lower portion of a probe arm is arranged at an end surface of a support seat; a first rotating shaft passes through a first through hole formed in the lower end of the probe arm and is connected with the support seat; and a second rotating shaft passes through a second through hole formed in the lower end of the probe arm and is connected with the support seat. The probe arm is fixed at the first rotating shaft by a first locking device and is fixed at the second rotating shaft by a second locking device. An opening is formed in the contact surface of the support seat and the first rotating shaft; a deformation sensor is arranged in the opening. A probe extending arm includes an elastic element and a probe; the elastic element is arranged at the upper end of the probe extending arm; and the probe is arranged in the elastic arm. And the probe extending arm is fixedly connected with the upper portion of the probe arm by a third locking device.