Abstract: The delay of fluid diverting and pressure releasing in cementing bumping pressure, usually caused by such reasons as metering error, poor shearing accuracy and freezing of shear pin, combining with the extremely high pump pressure resulted from delayed pump stop and inertia flow after that, often leads to great damage to casing and cementing equipment, and poor cementing quality therefor. A pressure bumping prediction device is thus developed to solve this problem. The prediction device, one or more, can be installed in a predetermined location in the casing string. In cementing, as the plug passes by the device, a surge pressure will be produced and can be readout on surface, and the operators then can take proper measures accordingly to ensure a successful cementing job. This device can also be used to determine if real pressure bumping is achieved. Field applications show that it is easy and reliable.