The invention relates to a high-efficiency condensing type heat exchanger which comprises a tubular shell, an upper-layer water tank, an upper spiral sleeve pipe, a middle-layer water tank, a lower spiral sleeve pipe, a lower-layer water tank and a U-shaped condensed water collection smoke exhauster. The heat energy generated in the combustion process of water exchange is used for lowering the temperature of the smoke generated in the combustion process, and the water vapor in the smoke is condensed into the liquid state from the gaseous state to generate condensed water, thereby absorbing the latent heat emitted in the condensation process and improving the heat exchange efficiency of the heat exchanger. In the invention, the shell has a dismountable internal structure, can be cleared and maintained easily, improves the heat exchange efficiency of the heat exchanger, is suitable for various products of gas-fired hot water, and is suitable for domestic gas-fired hot water heating equipment and the like.