The utility model discloses a condensing system of flue gas analysis preliminary treatment, including the acidification peristaltic pump, the tee bend ball valve, the drainage peristaltic pump, the dew point hygrometer, the sampling pump, hot exchange pipe of one -level glass and the hot exchange pipe of second grade glass, solution jar and acidification peristaltic pump connection, the acidification peristaltic pump is connected with the tee bend ball valve, the tee bend ball valve other end is connected with smoke incoming pipe, the evaporimeter is equipped with the evaporimeter filter core, hot exchange pipe of one -level glass and the hot exchange pipe of second grade glass insert in the evaporimeter filter core, the hot exchange pipe of one -level glass is connected with the tee bend ball valve, hot exchange pipe of one -level glass and the hot exchange pipe of second grade glass are connected, the hot exchange pipe of second grade glass is connected with the dew point hygrometer, the dew point hygrometer is connected with the sampling pump, hot exchange pipe of one -level glass and the hot exchange pipe's of second grade glass bottom all is equipped with the delivery port, hot exchange pipe of one -level glass and the hot exchange pipe's of second grade glass delivery port and drainage peristaltic pump connection, the splendid attire has phosphoric acid in the solution jar. The utility model discloses dewatering effect is good, and has reduced the sulfur dioxide rate of losing.