An on line experimental system was set up in a heating boiler so as to reproduce dusty working environments in heat recovery systems and to investigate heat transfer and fouling performance of different kinds of finned tube heat exchangers. Measurements are reported for the heat transfer coefficients, fouling and the effect of fouling on heat transfer performance of five different H-type finned tube heat exchangers. Fouling resistance and the weakened degree of heat transfer coefficient are employed to evaluate the effect of fouling on the heat transfer performance. Numerical simulations are also conducted on the fouling performance of each heat exchanger bundle and compared to the measurements. Double H-type fins can slightly reduce the heat transfer performance but also reduce fouling. Elliptical finned tubes with the same tube pitch decrease heat transfer performance and increase fouling, and with the same relative tube pitch, significantly increase the heat transfer performance before fouling, and can effectively reduce fouling.