The invention provides a pool type test device for a liquid heavy metal cooling reactor steam generator. The device comprises a sealing flange used for being connecting with a whole test table, a helium gas chamber is located on the sealing flange, a steam chamber is located on the helium gas chamber, the helium gas chamber and the steam chamber are independent to each other, the helium gas chamber is used for sealing, one side of the steam chamber is provided with a steam outlet, a water injecting opening flange is located above the steam chamber, bayonet pipe components used for heat exchange are fixed on the water injecting opening flange, and the bayonet pipe components pass through the steam chamber, the helium gas chamber and the sealing flange and extend into the overall test table.The device provided by the invention can effectively simulate a heat exchange process of the liquid heavy metal cooling reactor straight-tube steam generator, obtains thermal data of a heat exchanger, and guides design of a metal cooling reactor heat exchanger; and at the same time, the device can reduce test costs, provide reliable test simulated data, and improve efficiency and safety of reactor operation.