A Supercritical Water-cooled Nuclear Reactor (SCWR) is a Generation IV concept now being developed international. This work deliberated the influence of  supercritical pressures on alternative nuclear fuels, clad and coolant temperatures for different alternative nuclear fuels (MOx, UC and UC₂), For Mixed oxide (MO_X) fuel at different pressures, at P= 26 (MPa), the  maximum temperature  reaches to 1614), for hot channel and reaches to 795.8), for average channel but the clad temperature reaches to 615.8), for hot channel and reaches to 396.3), for average channel and for the coolant the temperature reaches to 541.4), for hot channel and reaches to 366.6), for average channel. For (UC) fuel at pressure of 26(MPa), the results shows that the max fuel temperature reaches to 1550), for hot channel and reaches to 770.1), for average channel while the clad temperature reaches to 615.8), for hot channel and reaches to 396.3), for average channel and for the coolant the temperature reaches to 541.4), for hot channel and reached to 366.6), for average channel. For (UC₂) at pressure of 26(MPa), the results demonstrate that the max fuel temperature reaches to 1566), for hot channel and reaches to 776.2), for average channel while the clad temperature reaches to 615.8), for hot channel and reaches to 369.3) and the coolant temperature reaches to 541.4), for hot channel and reaches to 366.6), for average channel.