Abstract: A phenomenon named frequency smear will happen to the characteristics of nonsteady malfunction in rotary machine system when making a conventional frequency spectrum analysis. To make up for the deficiency of conventional frequency spectrum analysis and establish the relationship between the malfunction characteristics and rotating speed, the waveform restructuring technique is used to develop the order sectioning analysis based on even-time sampling rate. A typical misalignment fault testing is therefore designed to perform on a rotor test stand so as to analyze the relevant signals by way of the order sectioning analysis. The results showed that the order sections can characterize the double/triple frequency of a misalignment fault in rotary machine system and the variation of its harmonic components with rotating speed. The order sectioning analysis is thus proved recognizable to the characteristics of nonsteady malfunctions to a certain extent.