The utility model provides a cup-upsetting testing device of a pipeline magnetic leakage corrosion detector for detecting the degree of the pipeline corrosion on line, and relates to the pipeline system technical field. The utility model is mainly composed of a testing table (1), a testing pipe section (2), a central base (3), a cup pressure panel (4), a cup upper flange (5), an air inlet pipe (7), a ball valve (8), a pressure transmitter (10), wherein, the central base (3) is fixed on the testing table (1), the cup upper flange which fixes the tested leather cup with the cup pressure panel (4) is fixed on the central base (3) provided with holes along the side direction, the central base (3) and the cup upper flange (5) are sleeved and buttoned on the testing table (1) through the testing pipe section (2) and connected with the testing table (1) steadily, the cup upper flange (5) is provided with the holes for the air inlet pipe (7) and the ball valve (8) passing through, a pipe line which stretches out of the central base (3) and passes through the testing table (1) is connected with the pressure transmitter (10). The utility model has the advantages of simple and reliable structure, easy and convenient testing operation and precise testing result and being a practical cup-upsetting testing device.