By introducing a phenoxy group into the straight alkyl group of the sodium soap of ordinary fatty acids, a novel modified soap——sodium 2-(4-nonylphenoxy) acetate (SNA) was synthesized. The molecular structure of the product was identified by FT-IR and 1H-NMR, and the purity of 98% of the product was confirmed by the results of two phase titration and HPLC measurement. Performance of SNA was measured both at pH 7 and pH 10, such as Krafft point (TK), surface tension, wetting time (WT), foam ability, calcium stability, lime soap dispersing requirement and emulsifying power, which was further compared with sodium soap of oleic acid (SOA) and sodium dodecylbenzene sulfonate (LAS). The experimental results show that SNA has the excellent solubility at low temperature (TK < 0 °C); the excellent pH-independent wettability (WT = 25 s) compared to SOA (WT  15 min); and the good concentration-independent defoamability. Therefore, SNA has the potential as a novel low-foaming soap-type penetrating agent.