A multi-port power delivery system includes a first universal serial bus (USB) port, a second USB port, a first power conversion unit, a second power conversion unit, a power delivery control circuit and a switch circuit. The first USB port is configured to output power delivered to a first power path. The second USB port is configured to output power delivered to a second power path. The first power conversion unit has a first output terminal coupled to the first power path. The second power conversion unit has a second output terminal coupled to the second power path. The power delivery control circuit generates a switch control signal according to first connection information on the first USB port and second connection information on the second USB port. The switch circuit selectively couples the first output terminal to the second output terminal according to the switch control signal.