First, the voltage is different
1. single-phase electricity: 220 volts voltage.
2. three-phase electricity: a.b.c between the 380v phase voltage.
Second, the property is different
1. single-phase electricity: a phase line (commonly known as a fire line) and a zero line of electrical energy transmission form, if necessary, there will be a third line (ground line), used to prevent electric shock.
2. three-phase electricity: by three frequencies of the same, equal amplitude, phase in turn difference of 120 degrees of AC potential composed of the power supply.