Abstract: Although the sonic soot cleaning techniques have been applied in boilers in power plants,petrochemicalworks and general industries world wide,still most of the correlated basic problems have not been well solved.In thispaper!by using Helmholtz integral equation,sound waves scattered by heat-exchanger tubes in boiler is numericallycalculated.Sound field distribution characteristics on the tube surfaces and around the tube group are obtained.Theresult is very important for the development of sonic soot cleaning techniques in boilers.