One of significant features of the impact test that has been less used so far is determination of the natural frequency of the tested specimen. The purpose of this research is to measure experimentally the natural frequency of tested steel using drop weight tear test (DWTT). For this purpose, wavelet transformation was used for the first time (in research field of high pressure gas transportation pipes) to analysis the acceleration signal from impact test. The acceleration signals during fracture test of the API X65 steel specimens were captured by an accelerometer and analyzed then using the wavelet transformation. The DWT tests were performed according to the API 5L standard using three Chevron Notched specimens. The specimens were cut from a spirally welded steel pipe and machined then to standard dimensions. Next, the acceleration signal was denoised using the universal threshold method on the detail coefficients. After each impact test, the captured acceleration signal which was highly noisy was decomposed into low and high-frequency bands using discrete wavelet transform from which wavelet coefficients obtained. By applying continuous wavelet transformation (cwt) on the denoised acceleration signals, the natural frequencies of tested samples were found. The average natural frequency obtained from three specimens for API X65 steel was 2.598 kHz. Furthermore, the natural frequency time interval was obtained which was in the first millisecond of the experiment. The comparison of obtained results with available data showed the capability of WT for accurate measurement of the natural frequency in drop weight tear testing.