The invention discloses a liquid sodium metal thermohydraulic experimental loop system. The loop system comprises a sodium filling system, a loop body, a vacuum system, an argon system and a glove box, wherein the sodium filling system comprises a sodium fusion tank and a sodium filter; the loop body mainly comprises a sodium storage tank, a pump box, a main electromagnetic pump, an auxiliary electromagnetic pump, a preheater, a test section, a radiator, a calibration barrel and a cold trap; and the glove box mainly comprises a sodium sampling analysis device. By the system, sodium filling operation can be realized, liquid sodium metal heat transfer flow characteristics are analyzed, liquid sodium metal is purified on line, an electromagnetic flowmeter is calibrated, and multiple functions of sampling analysis, detection and the like of the liquid sodium metal are realized.