The invention discloses a flue bend fixing device which comprises a square bend, a main flue fixing portion and a branch flue fixing portion. The square bend is formed from a metal plate. The invention further discloses a multi-stove soot and waste gas collection device which carried out flue fixing through the flue bend fixing device. Soot and waste gas exhausted from smoke exhaust ventilators of various gas stoves are collected and treated in a concentrated mode and then are exhausted into atmosphere. Accordingly, the exhaust efficiency is greatly improved, and air pollution is greatly reduced; meanwhile flue maintenance, cleaning and reliable fixing are convenient; the main flue fixing portion can be prevented from being disengaged out from the square bend, the square bend can be conveniently machined and formed from the metal plate, and waste of excessive leftover materials is avoided.