Configuring the Duplex Mode for an Interface in Auto-Negotiation Mode
# Set the duplex mode to full-duplex for Ethernet electrical interface GE0/0/1 working in auto-negotiation mode.
<HUAWEI> system-view [HUAWEI] interface gigabitethernet 0/0/1 [HUAWEI-GigabitEthernet0/0/1] negotiation auto [HUAWEI-GigabitEthernet0/0/1] auto duplex full
Configuring the Duplex Mode for an Interface in Non-Auto-Negotiation Mode
# Set the duplex mode to half-duplex for Ethernet electrical interface GE0/0/1 working in non-auto-negotiation mode.
<HUAWEI> system-view [HUAWEI] interface gigabitethernet 0/0/1 [HUAWEI-GigabitEthernet0/0/1] undo negotiation auto [HUAWEI-GigabitEthernet0/0/1] duplex half

Physical service interfaces of the S5710HI, S6700EI, S5720HI, S5720EI and S6720EI do not support the duplex mode configuration.
Physical service interfaces of the X1E series cards on a modular switch do not support the duplex mode configuration.
More Information: S Series Switches Common Operation Guide