The utility model relates to a desulfurizing slurry density measurement system's pressure measuring equipment in power plant's desulfurization prewashing tower, measuring device is including setting up in the prewashing tower pressure sensor of co -altitude department not, and each pressure sensor measures the pressure value that the prewashing tower corresponds the high desulfurizing slurry of department respectively. Through at the desulfurization prewashing tower pressure sensor of co -altitude department not to realization precision measurement of the desulfurizing slurry of co -altitude department not in to the prewashing tower, and then can accurate calculation draw the not co -altitude desulfurizing slurry of department pressure differential according to the measured value, reach the purpose of carrying out the accurate determination to the desulfurizing slurry pressure differential. And simultaneously, the utility model discloses simple structure, the effect is showing, suitable using widely.