Building pipeline connecting piece

The utility model discloses a building pipeline connecting piece which comprises a connecting outer cylinder, a middle plate is arranged in the connecting outer cylinder, a through hole is formed in the middle plate, two clamping blocks are arranged at the two ends of the connecting outer cylinder correspondingly, sleeves are arranged on the sides, deviating from each other, of the two clamping blocks correspondingly, and screw rods are rotationally arranged in the sleeves; the end, away from the sleeve, of the screw rod penetrates out of the connecting outer barrel, the screw rod is in threaded connection with the connecting outer barrel, and a driving assembly used for driving the two adjacent pipeline sections to be close to each other or away from each other in the length direction of the connecting outer barrel is arranged on the connecting outer barrel. The connecting piece has the effect of effectively reducing the situation that two sections of pipelines with different pipe diameters are difficult to