A new method for identifying the emulsion type of surfactant is introduced-volume balance value, that is, the ratio of hydrophilic group and hydrophobic group volumes in surfactant. The radius used in the volume for the VB value comes from the Pauling radius based on quantum chemistry. The result shows that the surfactant is an o/w emulsifying agent and water-soluble when the VB is more than 1, and is a w/o emulsifying agent and oil-soluble when the VB is less than 1. The VB value possesses additivity.