The invention provides a heat exchanger which comprises a tubular shell, a shell pass inlet, a shell pass outlet, a limit inlay, a tube pass inlet and a tube pass outlet, wherein both ends of the shell are respectively provided with a tube box and a tube plate, and a heat exchange tube and a baffling plate are arranged in the shell; the shell pass inlet and the shell pass outlet are formed in the tubular shell and axially vertical to the tubular shell; the tube pass inlet and the tube pass outlet are formed in the tube box; and a spiral flow guide ring is respectively arranged at the shell pass inlet and the tube pass inlet. According to the heat exchanger, a total-shell-pass nonlinear three-dimensional multi-runner spiral runner structural design is realized, so that the heat exchanger has the characteristics of high heat exchange efficiency, compact structure, easy machining, low maintenance cost, small vibration, long service life and the like and has wide application values in the fields of petrochemical industry, smelting, electric power, ship building, food, heat supply, energy saving and environmental protection; and particularly, under the condition of two-phase mixed media, the heat exchanger has the characteristics of strong homogenizing capacity and high heat exchange efficiency.