A universal joint assembly , comprising: a base , having an accommodating groove , a first opening and a second opening opposite to the first opening , wherein the accommodating groove is connected to the first opening and the second opening ; a ball shaft ; and a locking member , entering the accommodating groove through the first opening and pressing the ball shaft , characterized, in that the universal joint assembly further comprising: two clamping members , disposed inside the accommodating groove , wherein each of the two clamping members comprises a bearing portion , a fulcrum portion , and a clamping portion , the bearing portion is close to the first opening , an adjustable space (S) exists between an outer side of the bearing portion and an inner wall of the accommodating groove , the fulcrum portion is located between the bearing portion and the clamping portion , the fulcrum portion is in contact with the inner wall , and the clamping portion is close to the second opening and is in contact with the inner wall ; wherein the ball shaft is disposed between the two clamping members ; and the locking member presses the bearing portion , wherein the bearing portion moves toward the inner wall in the adjustable space (S), so that the two clamping members take a position where the fulcrum portion contacts the inner wall as a fulcrum and the clamping portion moves toward the ball shaft to clamp the ball shaft . a base , having an accommodating groove , a first opening and a second opening opposite to the first opening , wherein the accommodating groove is connected to the first opening and the second opening ; a ball shaft ; and a locking member , entering the accommodating groove through the first opening and pressing the ball shaft , characterized, in that the universal joint assembly further comprising: two clamping members , disposed inside the accommodating groove , wherein each of the two clamping members comprises a bearing portion , a fulcrum portion , and a clamping portion , the bearing portion is close to the first opening , an adjustable space (S) exists between an outer side of the bearing portion and an inner wall of the accommodating groove , the fulcrum portion is located between the bearing portion and the clamping portion , the fulcrum portion is in contact with the inner wall , and the clamping portion is close to the second opening and is in contact with the inner wall ; wherein the ball shaft is disposed between the two clamping members ; and the locking member presses the bearing portion , wherein the bearing portion moves toward the inner wall in the adjustable space (S), so that the two clamping members take a position where the fulcrum portion contacts the inner wall as a fulcrum and the clamping portion moves toward the ball shaft to clamp the ball shaft . two clamping members , disposed inside the accommodating groove , wherein each of the two clamping members comprises a bearing portion , a fulcrum portion , and a clamping portion , the bearing portion is close to the first opening , an adjustable space (S) exists between an outer side of the bearing portion and an inner wall of the accommodating groove , the fulcrum portion is located between the bearing portion and the clamping portion , the fulcrum portion is in contact with the inner wall , and the clamping portion is close to the second opening and is in contact with the inner wall ; wherein the ball shaft is disposed between the two clamping members ; and the locking member presses the bearing portion , wherein the bearing portion moves toward the inner wall in the adjustable space (S), so that the two clamping members take a position where the fulcrum portion contacts the inner wall as a fulcrum and the clamping portion moves toward the ball shaft to clamp the ball shaft . <EOS>