First, voltage is different
1. Single-phase power: 220 VOLTS.
2. Three-phase power: 380V phase voltage between ABC.
Two, different attributes
1. Single-phase electricity: the form of power transmission of one phase line (commonly known as live wire) and zero line, and three lines (ground wire) if necessary, to prevent electric shock.
2. Three-phase power: a power supply composed of three AC potentials with the same frequency, the same amplitude and 120 degrees of phase difference.