The utility model discloses a desulfurization medicine recovery system of semi -dry desulfurization device, this desulfurization medicine recovery system of semi -dry desulfurization device include upper portion be equipped with the exhanst gas outlet reaction tower, with the sack cleaner of exhanst gas outlet intercommunication, establish feed back pipe under the sack cleaner, the lower part of reaction tower is equipped with flue gas inlet, import of drugs, moisture import, the one end of feed back pipe is established sack cleaner lower part one end is established the reaction tower lower part, the feed back pipe will the reaction tower with the sack cleaner intercommunication, feed back pipe intercommunication the one end of sack cleaner is higher than the other end of feed back pipe, the feed back pipe is close to reaction tower department is equipped with the separator that is used for isolated flue gas and can opens and shuts, the dust that contains the desulfurization medicine that has that partial sack cleaner isolates transported back the reaction tower continue with the flue gas reaction for the more abundant advantage that the desulfurization medicine was utilized.