This invention provides an airlift loop reactor without the need for external gases, which comprises main reactor (1), gas circulation line (2), gas pump (3), jacket (4), gas inlet (5), gas outlet (6), flow guider (7), gas flowmeter (8), feed inlet (9) and discharge opening (10). It is characterized by : connecting the gas outlet (6) on top of the airlift loop reactor to the gas inlet (5) at the bottom of the reactor, and installing the gas pump (3) in gas circulation line (2), hence directly using the internal gases as the circulation impetus, so that gases are directed by the gas circulation line (2) back to the bottom of the reactor after flowing out from the top of the reactor and then re-ejected into the reactor by the gas pump (3) and used as circulation impetus again. Compared to common airlift loop reactors which use external gases as the impetus; the airlift loop reactor of the present invention effectively reduces the cost of using external gases and hence diminishes production costs. Therefore, it has very good prospects for industrial application.