The invention discloses an integrated device for measuring slurry density and pH(potential of hydrogen) in a lime(stone)-plaster wet desulphurization tower. The integrated device comprises a desulfurization tower slurry pond, a solid-liquid separator and a pit, wherein the bottom end of the desulfurization tower slurry pond is connected with the solid-liquid separator through a feed pipeline; the solid-liquid separator comprises a casing, wherein a cone hopper is arranged at the bottom end of the casing, a discharge pipeline is arranged at the bottom part of the cone hopper to be used for being communicated with the pit, a soil discharging motorized valve is arranged on the discharge pipeline, an overflow pipeline is arranged on one side of the upper end of the casing to be used for being communicated with the pit, and a pipeline type densimeter and a washing water pipeline are arranged on the feed pipeline; a pH probe is arranged at the top end of the casing of the solid-liquid separator, a washing helix spray nozzle is arranged directly below the probe, and the washing helix spray nozzle is connected with the washing water pipeline. Through the use of the integrated device, the slurry density and the pH in the desulphurization tower can be monitored at the same time in an on-line manner, the phenomena that the deviation of measurement data is larger, even data is distorted and the replacement of a measuring component is frequent, which are caused by the encrustment and the serious erosive wear of a traditional densimeter and a traditional pH meter probe, are avoided, so that the long-term high-efficiency operation of a desulfurization system is ensured, and the investment and operation costs are reduced.