The invention provides a sawtooth porous type plate-fin heat exchanger. The existing plate-fin heat exchanger is formed by heat exchange fins, a baffle, a seal strip, a flow deflector, an end plate, an end socket, a liquid inlet and outlet connection pipe and the like. Under the condition that the existing structure is not changed, the characteristics of porous fins and sawtooth fins are combined, many short fragments are cut in the teeth length direction of the porous fin, and sawtooth shapes are staggered at intervals in the teeth length direction of the porous fin to obtain the sawtooth porous type fins. When heat exchange fluid flows in a runner, the sawtooth facilitates fluid disturbance, the heat exchange function is strengthened, and the heat exchange efficiency of the heat exchange fin is improved. By adopting the technical scheme, the plate-fin heat exchanger is formed by porous sawtooth fins; the heat exchange effect is strengthened; the heat exchange efficiency of the heat exchange fin is improved, and the structure of the plate-fin heat exchanger is more compact.