As one of the most important algorithms for white-light interferometry, the spacial frequency-domain algorithm (FDA) is widely applied in the field of micro-nano structure surface topography measurement. However, traditional FDA measurement result involves phase error accumulation effect caused by sample slope and the surface fluctuation, and the phase error is closely related with the offset of zero optical path difference (OPD) positon in the interference signal. This paper explains the reason of phase error accumulation effect existing in traditional FDA, and proposes an envelope-signal-assisted analysis (ESAA) method based on traditional FDA to exhibit the phase error accumulation. The ESAA method firstly perform a symmetric adjustment for the offset of zero OPD position existing in the original interference signal. Then, the FDA is applied for the adjusted symmetric interference signal which can restrict the phase error accumulation effect as more as possible. To demonsrate the validity of proposed method, both simulation and experimental analysis are elaborated and discussed.