Abstract: Iso-tridecanol polyoxyethylene ether phosphate was synthesized in this text by phosphorylation using phosphorus pentoxide. The effects of proportions of raw material, time and temperature of esterification, modes and hydrolyze time on the alkali permeability of iso-tridecanol polyoxyethylene ether phosphate were discussed. The results revealed the proportion of monoester to disaster was important factor to the alkali permeability of iso-tridecanol polyoxyethylene ether phosphate, and along with the proportion is bigger, the better performance of alkali permeability. The optimum synthesis process was acquired as following: the ratio of n(AEO)∶n(P2O5)=3∶1, esterifying at 90℃ for 4 h, and add given volume of water at 90℃ for hydrolyzing 3h. This synthesis process offered the best alkali permeability of iso-tridecanol polyoxyethylene ether phosphate. In addition, the iso-tridecanol polyoxyethylene ether phosphate has been tested and characterization by FTIR, HPLC methods in order to discuss the ether esterification mechanism.