An adjustment structure and an adjustment method therefor, a sealing member, a coaxial cable, a gimbal and a mobile apparatus are provided. The arm adjustment structure includes a base, an arm, and a sealing member. The arm is capable of moving relative to the base, and a clearing slot is disposed on the arm. The sealing member is disposed between the base and the arm, and is capable of being located at the clearing slot to cover the clearing slot. The sealing member is disposed between the base and the arm, and capable of being located at the clearing slot to cover the clearing slot to prevent the clearing slot from being exposed, and prevent foreign matters such as water droplets, sand, and dust from entering the gimbal through the clearing slot and affecting normal use of the gimbal.