Abstract: A mathematics model of determining sound power by using the scanning method is developed.It is assumedthat the scanning speed is constant and the noise source is stationary.The accuracy of estimating sound power alongsome simple paths on the surfaces such as rectangle,disc and hemisphere is analyzed.It is argued that the accuracyof estimating sound power is strongly depended on a suitable selection of scan path.The accurate estimation of soundpower can be made by scanning along some simple paths.