Being affected by the bend of pipes, it is difficult to obtain good original records in acoustic penetrating test of pile foundation. In order to eliminate the affection, based on one-dimensional wavelet analysis theory, analyzing the characteristic of the signal deriving from the bend pipe in acoustic penetrating test, the new modifying model is founded. By simulating on computer the most effective one in familiar thirty-seven kinds of wavelet functions to the model is obtained. The test signal deriving from a pile of a bridge is modified with this method. The result shows that the new method not only dispels the influence of bend pipe, but also holds the useful high frequency signal. This method reduces the happening of oversight and wrong test and shows a nice representation in engineering.